diff --git a/index.d.ts b/index.d.ts
index 0960d93..0b87bfa 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -278,7 +278,7 @@ declare class DateFormatter {
     #private;
 }
 declare namespace DateFormatter {
-    export { DateFormatter as default, DateFormatter, dateFormat, getWeekOfYear, getDayName, standardMasks, standardMaskNames, i18n, I18n, DateFn };
+    export { DateFormatter as default, DateFormatter, dateformat, getWeekOfYear, getDayName, standardMasks, standardMaskNames, i18n, I18n, DateFn };
 }
 /**
  * @param {string | number | Date} [date=new Date()]
@@ -286,7 +286,7 @@ declare namespace DateFormatter {
  * @param {boolean} [utc=false]
  * @param {boolean} [gmt=true]
  */
-declare function dateFormat(date?: string | number | Date, mask?: string, utc?: boolean, gmt?: boolean): string;
+declare function dateformat(date?: string | number | Date, mask?: string, utc?: boolean, gmt?: boolean): string;
 /**
  * Get the ISO 8601 week number for a given date.
  *
diff --git a/index.js b/index.js
index 3d88383..8d2a816 100644
--- a/index.js
+++ b/index.js
@@ -854,7 +854,7 @@ class DateFormatter {
  * @param {boolean} [utc=false]
  * @param {boolean} [gmt=true]
  */
-function dateFormat (date, mask, utc, gmt) {
+function dateformat (date, mask, utc, gmt) {
   if (typeof date === 'string' || typeof date === 'number') {
     date = new Date(date)
   }
@@ -889,7 +889,7 @@ function dateFormat (date, mask, utc, gmt) {
 module.exports = DateFormatter
 module.exports.default = DateFormatter
 module.exports.DateFormatter = DateFormatter
-module.exports.dateFormat = dateFormat
+module.exports.dateformat = dateformat
 module.exports.getWeekOfYear = getWeekOfYear
 module.exports.getDayName = getDayName
 module.exports.standardMasks = standardMasks
diff --git a/test/dateformat/test_dayofweek.js b/test/dateformat/test_dayofweek.js
index 1295cea..27884a5 100644
--- a/test/dateformat/test_dayofweek.js
+++ b/test/dateformat/test_dayofweek.js
@@ -2,14 +2,14 @@
 
 const { describe, it } = require('node:test')
 
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe('dayOfWeek', function () {
   it('should correctly format the timezone part', function (t) {
     const start = 10 // the 10 of March 2013 is a Sunday
     for (let dow = 1; dow <= 7; dow++) {
       const date = new Date('2013-03-' + (start + dow))
-      const N = dateFormat(date, 'N')
+      const N = dateformat(date, 'N')
       t.assert.strictEqual(N, String(dow))
     }
   })
diff --git a/test/dateformat/test_formats.js b/test/dateformat/test_formats.js
index d29098d..6410751 100644
--- a/test/dateformat/test_formats.js
+++ b/test/dateformat/test_formats.js
@@ -1,5 +1,5 @@
 const { describe, it } = require('node:test')
-const { dateFormat, standardMasks: masks } = require('../../index.js')
+const { dateformat, standardMasks: masks } = require('../../index.js')
 
 const expects = {
   default: 'Sat Mar 08 2014 13:19:44',
@@ -61,14 +61,14 @@ describe('dateformat([now], [mask])', function () {
         )
         expected = now.toISOString().replace(/\.000/g, '')
       }
-      const actual = dateFormat(now, key)
+      const actual = dateformat(now, key)
       t.assert.strictEqual(actual, expected)
     })
   })
   it('should use `default` mask, when `mask` is empty', (t) => {
     const now = new Date(2014, 2, 8, 13, 19, 44)
     const expected = expects['default']
-    const actual = dateFormat(now)
+    const actual = dateformat(now)
 
     t.assert.strictEqual(actual, expected)
   })
diff --git a/test/dateformat/test_isoutcdatetime.js b/test/dateformat/test_isoutcdatetime.js
index 086cfc2..effb877 100644
--- a/test/dateformat/test_isoutcdatetime.js
+++ b/test/dateformat/test_isoutcdatetime.js
@@ -1,12 +1,12 @@
 const { describe, it } = require('node:test')
 
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe('isoUtcDateTime', function () {
   it('should correctly format the timezone part', (t) => {
-    const actual = dateFormat('2014-06-02T13:23:21-08:00', 'isoUtcDateTime')
+    const actual = dateformat('2014-06-02T13:23:21-08:00', 'isoUtcDateTime')
     t.assert.strictEqual(actual, '2014-06-02T21:23:21Z')
-    const epochTime = dateFormat(0, 'isoUtcDateTime')
+    const epochTime = dateformat(0, 'isoUtcDateTime')
     t.assert.strictEqual(epochTime, '1970-01-01T00:00:00Z')
   })
 })
diff --git a/test/dateformat/test_mask-d.js b/test/dateformat/test_mask-d.js
index 8ae9ba4..f0ec667 100644
--- a/test/dateformat/test_mask-d.js
+++ b/test/dateformat/test_mask-d.js
@@ -1,28 +1,28 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'd'", function () {
   it("should format '1993-03-12' as '12'", (t) => {
     const date = new Date('1993-03-12')
-    const d = dateFormat(date, 'd')
+    const d = dateformat(date, 'd')
     t.assert.strictEqual(d, '12')
   })
 
   it("should format '2020-11-1' as '1'", (t) => {
     const date = new Date('2020-11-1')
-    const d = dateFormat(date, 'd')
+    const d = dateformat(date, 'd')
     t.assert.strictEqual(d, '1')
   })
 
   it("should format '1830-01-20' as '20'", (t) => {
     const date = new Date('1830-01-20')
-    const d = dateFormat(date, 'd')
+    const d = dateformat(date, 'd')
     t.assert.strictEqual(d, '20')
   })
 
   it("should not format '1830-01-06' as '06'", (t) => {
     const date = new Date('1830-01-20')
-    const d = dateFormat(date, 'd')
+    const d = dateformat(date, 'd')
     t.assert.notStrictEqual(d, '06')
   })
 })
diff --git a/test/dateformat/test_mask-dd.js b/test/dateformat/test_mask-dd.js
index b84c8e1..ef05ef8 100644
--- a/test/dateformat/test_mask-dd.js
+++ b/test/dateformat/test_mask-dd.js
@@ -1,28 +1,28 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'dd'", function () {
   it("should format '2003-9-11' as '11'", (t) => {
     const date = new Date('2003-9-11')
-    const d = dateFormat(date, 'dd')
+    const d = dateformat(date, 'dd')
     t.assert.strictEqual(d, '11')
   })
 
   it("should format '1992-02-2' as '02'", (t) => {
     const date = new Date('1992-02-2')
-    const d = dateFormat(date, 'dd')
+    const d = dateformat(date, 'dd')
     t.assert.strictEqual(d, '02')
   })
 
   it("should format '1032-12-07' as '07'", (t) => {
     const date = new Date('1032-12-07')
-    const d = dateFormat(date, 'dd')
+    const d = dateformat(date, 'dd')
     t.assert.strictEqual(d, '07')
   })
 
   it("should not format '2077-10-06' as '6'", (t) => {
     const date = new Date('2077-10-06')
-    const d = dateFormat(date, 'dd')
+    const d = dateformat(date, 'dd')
     t.assert.notStrictEqual(d, '6')
   })
 })
diff --git a/test/dateformat/test_mask-ddd.js b/test/dateformat/test_mask-ddd.js
index 69bcb85..17dd6f6 100644
--- a/test/dateformat/test_mask-ddd.js
+++ b/test/dateformat/test_mask-ddd.js
@@ -1,22 +1,22 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'ddd'", function () {
   it("should format '2023-01-07' as 'Sat'", (t) => {
     const date = new Date('2023-01-07')
-    const d = dateFormat(date, 'ddd')
+    const d = dateformat(date, 'ddd')
     t.assert.strictEqual(d, 'Sat')
   })
 
   it("should format '1873-12-17' as 'Wed'", (t) => {
     const date = new Date('1873-12-17')
-    const d = dateFormat(date, 'ddd')
+    const d = dateformat(date, 'ddd')
     t.assert.strictEqual(d, 'Wed')
   })
 
   it("should format '2112-10-25' as 'Tue'", (t) => {
     const date = new Date('2112-10-25')
-    const d = dateFormat(date, 'ddd')
+    const d = dateformat(date, 'ddd')
     t.assert.strictEqual(d, 'Tue')
   })
 })
diff --git a/test/dateformat/test_mask-dddd.js b/test/dateformat/test_mask-dddd.js
index 96b8d3e..8be9faa 100644
--- a/test/dateformat/test_mask-dddd.js
+++ b/test/dateformat/test_mask-dddd.js
@@ -1,22 +1,22 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'dddd'", function () {
   it("should format '1934-11-13' as 'Tuesday'", (t) => {
     const date = new Date('1934-11-13')
-    const d = dateFormat(date, 'dddd')
+    const d = dateformat(date, 'dddd')
     t.assert.strictEqual(d, 'Tuesday')
   })
 
   it("should format '1834-01-2' as 'Thursday'", (t) => {
     const date = new Date('1834-01-2')
-    const d = dateFormat(date, 'dddd')
+    const d = dateformat(date, 'dddd')
     t.assert.strictEqual(d, 'Thursday')
   })
 
   it("should format '2077-7-22' as 'Thursday'", (t) => {
     const date = new Date('2077-7-22')
-    const d = dateFormat(date, 'dddd')
+    const d = dateformat(date, 'dddd')
     t.assert.strictEqual(d, 'Thursday')
   })
 })
diff --git a/test/dateformat/test_mask-h.js b/test/dateformat/test_mask-h.js
index 71e15cb..4effa7d 100644
--- a/test/dateformat/test_mask-h.js
+++ b/test/dateformat/test_mask-h.js
@@ -1,26 +1,26 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'h'", function () {
   it("should format '2020-10-22T22:10:59.736' as '10'", (t) => {
     const date = new Date('2020-10-22T22:10:59.736')
-    const d = dateFormat(date, 'h')
+    const d = dateformat(date, 'h')
     t.assert.strictEqual(d, '10')
   })
 
   it("should format '2020-10-13T13:30:41.278' as '1'", (t) => {
     const date = new Date('2020-10-13T13:30:41.278')
-    const d = dateFormat(date, 'h')
+    const d = dateformat(date, 'h')
     t.assert.strictEqual(d, '1')
   })
 
   it("should format '1993-02-19T03:18:18.711' as '3'", (t) => {
-    const d = dateFormat('1993-02-19T03:18:18.711', 'h')
+    const d = dateformat('1993-02-19T03:18:18.711', 'h')
     t.assert.strictEqual(d, '3')
   })
 
   it("should format '2134-01-25T02:20:42.816' as '2'", (t) => {
-    const d = dateFormat('2134-01-25T02:20:42.816', 'h')
+    const d = dateformat('2134-01-25T02:20:42.816', 'h')
     t.assert.strictEqual(d, '2')
   })
 })
diff --git a/test/dateformat/test_mask-h_.js b/test/dateformat/test_mask-h_.js
index 73a3bc7..db04747 100644
--- a/test/dateformat/test_mask-h_.js
+++ b/test/dateformat/test_mask-h_.js
@@ -1,26 +1,26 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'H'", function () {
   it("should format '1883-03-22T07:35:26.419' as '7'", (t) => {
     const date = new Date('1883-03-22T07:35:26.419')
-    const d = dateFormat(date, 'H')
+    const d = dateformat(date, 'H')
     t.assert.strictEqual(d, '7')
   })
 
   it("should format '2012-11-07T14:39:48.988' as '14'", (t) => {
     const date = new Date('2012-11-07T14:39:48.988')
-    const d = dateFormat(date, 'H')
+    const d = dateformat(date, 'H')
     t.assert.strictEqual(d, '14')
   })
 
   it("should format '1882-01-16T19:37:45.965' as '19'", (t) => {
-    const d = dateFormat('1882-01-16T19:37:45.965', 'H')
+    const d = dateformat('1882-01-16T19:37:45.965', 'H')
     t.assert.strictEqual(d, '19')
   })
 
   it("should format '2020-08-29T11:20:47.128' as '11'", (t) => {
-    const d = dateFormat('2020-08-29T11:20:47.128', 'H')
+    const d = dateformat('2020-08-29T11:20:47.128', 'H')
     t.assert.strictEqual(d, '11')
   })
 })
diff --git a/test/dateformat/test_mask-h_h_.js b/test/dateformat/test_mask-h_h_.js
index 108c0f0..effb0b6 100644
--- a/test/dateformat/test_mask-h_h_.js
+++ b/test/dateformat/test_mask-h_h_.js
@@ -1,26 +1,26 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'HH'", function () {
   it("should format '1872-02-01T15:55:16.524' as '15'", (t) => {
     const date = new Date('1872-02-01T15:55:16.524')
-    const d = dateFormat(date, 'HH')
+    const d = dateformat(date, 'HH')
     t.assert.strictEqual(d, '15')
   })
 
   it("should format '2020-10-08T14:32:24.438' as '14'", (t) => {
     const date = new Date('2020-10-08T14:32:24.438')
-    const d = dateFormat(date, 'HH')
+    const d = dateformat(date, 'HH')
     t.assert.strictEqual(d, '14')
   })
 
   it("should format '2077-12-24T04:20:55.795' as '04'", (t) => {
-    const d = dateFormat('2077-12-24T04:20:55.795', 'HH')
+    const d = dateformat('2077-12-24T04:20:55.795', 'HH')
     t.assert.strictEqual(d, '04')
   })
 
   it("should format '1782-02-11T01:09:41.403' as '01'", (t) => {
-    const d = dateFormat('1782-02-11T01:09:41.403', 'HH')
+    const d = dateformat('1782-02-11T01:09:41.403', 'HH')
     t.assert.strictEqual(d, '01')
   })
 })
diff --git a/test/dateformat/test_mask-hh.js b/test/dateformat/test_mask-hh.js
index 5722e85..3c041e0 100644
--- a/test/dateformat/test_mask-hh.js
+++ b/test/dateformat/test_mask-hh.js
@@ -1,26 +1,26 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'hh'", function () {
   it("should format '1987-02-11T11:03:16.637' as '11'", (t) => {
     const date = new Date('1987-02-11T11:03:16.637')
-    const d = dateFormat(date, 'hh')
+    const d = dateformat(date, 'hh')
     t.assert.strictEqual(d, '11')
   })
 
   it("should format '2014-09-28T04:29:52.509' as '04'", (t) => {
     const date = new Date('2020-09-28T04:29:52.509')
-    const d = dateFormat(date, 'hh')
+    const d = dateformat(date, 'hh')
     t.assert.strictEqual(d, '04')
   })
 
   it("should format '2001-08-02T19:14:19.263' as '07'", (t) => {
-    const d = dateFormat('2001-08-02T19:14:19.263', 'hh')
+    const d = dateformat('2001-08-02T19:14:19.263', 'hh')
     t.assert.strictEqual(d, '07')
   })
 
   it("should format '1872-01-22T19:26:01.744' as '07'", (t) => {
-    const d = dateFormat('1872-01-22T19:26:01.744', 'hh')
+    const d = dateformat('1872-01-22T19:26:01.744', 'hh')
     t.assert.strictEqual(d, '07')
   })
 })
diff --git a/test/dateformat/test_mask-l.js b/test/dateformat/test_mask-l.js
index 89f0cf4..642d267 100644
--- a/test/dateformat/test_mask-l.js
+++ b/test/dateformat/test_mask-l.js
@@ -1,26 +1,26 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'l'", function () {
   it("should format '2020-10-10T08:48:02.436' as '436'", (t) => {
     const date = new Date('2020-10-10T08:48:02.436')
-    const d = dateFormat(date, 'l')
+    const d = dateformat(date, 'l')
     t.assert.strictEqual(d, '436')
   })
 
   it("should format '1993-02-16T14:22:12.654' as '654'", (t) => {
     const date = new Date('1993-02-16T14:22:12.654')
-    const d = dateFormat(date, 'l')
+    const d = dateformat(date, 'l')
     t.assert.strictEqual(d, '654')
   })
 
   it("should format '2076-01-03T18:23:30.064' as '064'", (t) => {
-    const d = dateFormat('2076-01-03T18:23:30.064', 'l')
+    const d = dateformat('2076-01-03T18:23:30.064', 'l')
     t.assert.strictEqual(d, '064')
   })
 
   it("should format '2002-12-25T19:35:55.655' as '655'", (t) => {
-    const d = dateFormat('2002-12-25T19:35:55.655', 'l')
+    const d = dateformat('2002-12-25T19:35:55.655', 'l')
     t.assert.strictEqual(d, '655')
   })
 })
diff --git a/test/dateformat/test_mask-l_.js b/test/dateformat/test_mask-l_.js
index ef67ce6..356fe3d 100644
--- a/test/dateformat/test_mask-l_.js
+++ b/test/dateformat/test_mask-l_.js
@@ -1,31 +1,31 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'L'", function () {
   it("should format '2020-10-10T08:48:02.436' as '44'", (t) => {
     const date = new Date('2020-10-10T08:48:02.436')
-    const d = dateFormat(date, 'L')
+    const d = dateformat(date, 'L')
     t.assert.strictEqual(d, '43')
   })
 
   it("should format '1993-02-16T14:22:12.654' as '65'", (t) => {
     const date = new Date('1993-02-16T14:22:12.654')
-    const d = dateFormat(date, 'L')
+    const d = dateformat(date, 'L')
     t.assert.strictEqual(d, '65')
   })
 
   it("should format '2076-01-03T18:23:30.064' as '06'", (t) => {
-    const d = dateFormat('2076-01-03T18:23:30.064', 'L')
+    const d = dateformat('2076-01-03T18:23:30.064', 'L')
     t.assert.strictEqual(d, '06')
   })
 
   it("should format '2002-12-25T19:35:55.655' as '66'", (t) => {
-    const d = dateFormat('2002-12-25T19:35:55.655', 'L')
+    const d = dateformat('2002-12-25T19:35:55.655', 'L')
     t.assert.strictEqual(d, '65')
   })
 
   it("should format '2126-07-23T03:15:25.999' as '99'", (t) => {
-    const d = dateFormat('2126-07-23T03:15:25.999', 'L')
+    const d = dateformat('2126-07-23T03:15:25.999', 'L')
     t.assert.strictEqual(d, '99')
   })
 })
diff --git a/test/dateformat/test_mask-m.js b/test/dateformat/test_mask-m.js
index 746c186..cc7c27d 100644
--- a/test/dateformat/test_mask-m.js
+++ b/test/dateformat/test_mask-m.js
@@ -1,28 +1,28 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'm'", function () {
   it("should format '1974-02-7' as '2'", (t) => {
     const date = new Date('1974-02-7')
-    const d = dateFormat(date, 'm')
+    const d = dateformat(date, 'm')
     t.assert.strictEqual(d, '2')
   })
 
   it("should format '1992-09-03' as '9'", (t) => {
     const date = new Date('1992-09-03')
-    const d = dateFormat(date, 'm')
+    const d = dateformat(date, 'm')
     t.assert.strictEqual(d, '9')
   })
 
   it("should format '2043-12-22' as '12'", (t) => {
     const date = new Date('2043-12-22')
-    const d = dateFormat(date, 'm')
+    const d = dateformat(date, 'm')
     t.assert.strictEqual(d, '12')
   })
 
   it("should format '1800-01-01' as '1'", (t) => {
     const date = new Date('1800-01-01')
-    const d = dateFormat(date, 'm')
+    const d = dateformat(date, 'm')
     t.assert.strictEqual(d, '1')
   })
 })
diff --git a/test/dateformat/test_mask-m_.js b/test/dateformat/test_mask-m_.js
index 69d9922..6d9d9bd 100644
--- a/test/dateformat/test_mask-m_.js
+++ b/test/dateformat/test_mask-m_.js
@@ -1,26 +1,26 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'M'", function () {
   it("should format '1993-02-12T17:36:01.128' as '36'", (t) => {
     const date = new Date('1993-02-12T17:36:01.128')
-    const d = dateFormat(date, 'M')
+    const d = dateformat(date, 'M')
     t.assert.strictEqual(d, '36')
   })
 
   it("should format '2013-11-02T07:00:54.270' as '0'", (t) => {
     const date = new Date('2013-11-02T07:00:54.270')
-    const d = dateFormat(date, 'M')
+    const d = dateformat(date, 'M')
     t.assert.strictEqual(d, '0')
   })
 
   it("should format '1873-01-04T11:11:34.700' as '11'", (t) => {
-    const d = dateFormat('1873-01-04T11:11:34.700', 'M')
+    const d = dateformat('1873-01-04T11:11:34.700', 'M')
     t.assert.strictEqual(d, '11')
   })
 
   it("should format '1734-12-07T09:05:07.972' as '5'", (t) => {
-    const d = dateFormat('1734-12-07T09:05:07.972', 'M')
+    const d = dateformat('1734-12-07T09:05:07.972', 'M')
     t.assert.strictEqual(d, '5')
   })
 })
diff --git a/test/dateformat/test_mask-m_m_.js b/test/dateformat/test_mask-m_m_.js
index 50f3bfe..06b0565 100644
--- a/test/dateformat/test_mask-m_m_.js
+++ b/test/dateformat/test_mask-m_m_.js
@@ -1,26 +1,26 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'MM'", function () {
   it("should format '1876-07-11T13:19:36.341' as '19'", (t) => {
     const date = new Date('1876-07-11T13:19:36.341')
-    const d = dateFormat(date, 'MM')
+    const d = dateformat(date, 'MM')
     t.assert.strictEqual(d, '19')
   })
 
   it("should format '2013-01-23T07:08:07.942' as '08'", (t) => {
     const date = new Date('2013-01-23T07:08:07.942')
-    const d = dateFormat(date, 'MM')
+    const d = dateformat(date, 'MM')
     t.assert.strictEqual(d, '08')
   })
 
   it("should format '1982-12-03T08:04:07.203' as '04'", (t) => {
-    const d = dateFormat('1982-12-03T08:04:07.203', 'MM')
+    const d = dateformat('1982-12-03T08:04:07.203', 'MM')
     t.assert.strictEqual(d, '04')
   })
 
   it("should format '2063-09-03T02:38:08.815' as '38'", (t) => {
-    const d = dateFormat('2063-09-03T02:38:08.815', 'MM')
+    const d = dateformat('2063-09-03T02:38:08.815', 'MM')
     t.assert.strictEqual(d, '38')
   })
 })
diff --git a/test/dateformat/test_mask-mm.js b/test/dateformat/test_mask-mm.js
index 8e15bbd..bf213d9 100644
--- a/test/dateformat/test_mask-mm.js
+++ b/test/dateformat/test_mask-mm.js
@@ -1,22 +1,22 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'mm'", function () {
   it("should format '2014-11-17' as '11'", (t) => {
     const date = new Date('2014-11-17')
-    const d = dateFormat(date, 'mm')
+    const d = dateformat(date, 'mm')
     t.assert.strictEqual(d, '11')
   })
 
   it("should format '1992-02-11' as '02'", (t) => {
     const date = new Date('1992-02-11')
-    const d = dateFormat(date, 'mm')
+    const d = dateformat(date, 'mm')
     t.assert.strictEqual(d, '02')
   })
 
   it("should format '2077-01-25' as '01'", (t) => {
     const date = new Date('2077-01-25')
-    const d = dateFormat(date, 'mm')
+    const d = dateformat(date, 'mm')
     t.assert.strictEqual(d, '01')
   })
 })
diff --git a/test/dateformat/test_mask-mmm.js b/test/dateformat/test_mask-mmm.js
index 62f0214..fc2d94e 100644
--- a/test/dateformat/test_mask-mmm.js
+++ b/test/dateformat/test_mask-mmm.js
@@ -1,22 +1,22 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'mmm'", function () {
   it("should format '2099-1-11' as 'Jan'", (t) => {
     const date = new Date('2099-1-11')
-    const d = dateFormat(date, 'mmm')
+    const d = dateformat(date, 'mmm')
     t.assert.strictEqual(d, 'Jan')
   })
 
   it("should format '1982-10-01' as 'Oct'", (t) => {
     const date = new Date('1982-10-01')
-    const d = dateFormat(date, 'mmm')
+    const d = dateformat(date, 'mmm')
     t.assert.strictEqual(d, 'Oct')
   })
 
   it("should format '1871-03-22' as 'Mar'", (t) => {
     const date = new Date('1871-03-22')
-    const d = dateFormat(date, 'mmm')
+    const d = dateformat(date, 'mmm')
     t.assert.strictEqual(d, 'Mar')
   })
 })
diff --git a/test/dateformat/test_mask-mmmm.js b/test/dateformat/test_mask-mmmm.js
index dc5280f..a1c80f7 100644
--- a/test/dateformat/test_mask-mmmm.js
+++ b/test/dateformat/test_mask-mmmm.js
@@ -1,22 +1,22 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'mmmm'", function () {
   it("should format '1993-02-11' as 'February'", function (t) {
     const date = new Date('1993-02-11')
-    const d = dateFormat(date, 'mmmm')
+    const d = dateformat(date, 'mmmm')
     t.assert.strictEqual(d, 'February')
   })
 
   it("should format '2023-11-13' as 'November'", function (t) {
     const date = new Date('2023-11-13')
-    const d = dateFormat(date, 'mmmm')
+    const d = dateformat(date, 'mmmm')
     t.assert.strictEqual(d, 'November')
   })
 
   it("should format '2077-10-01' as 'October'", function (t) {
     const date = new Date('2077-10-01')
-    const d = dateFormat(date, 'mmmm')
+    const d = dateformat(date, 'mmmm')
     t.assert.strictEqual(d, 'October')
   })
 })
diff --git a/test/dateformat/test_mask-n_.js b/test/dateformat/test_mask-n_.js
index fc0392a..a9b55a2 100644
--- a/test/dateformat/test_mask-n_.js
+++ b/test/dateformat/test_mask-n_.js
@@ -1,31 +1,31 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'N'", function () {
   it("should format '1984-02-7' as '2'", (t) => {
     const date = new Date('1984-02-7')
-    const d = dateFormat(date, 'N')
+    const d = dateformat(date, 'N')
     t.assert.strictEqual(d, '2')
   })
 
   it("should format '2013-01-17' as '4'", (t) => {
     const date = new Date('2013-01-17')
-    const d = dateFormat(date, 'N')
+    const d = dateformat(date, 'N')
     t.assert.strictEqual(d, '4')
   })
 
   it("should format '2034-11-24' as '5'", (t) => {
-    const d = dateFormat('2034-11-24', 'N')
+    const d = dateformat('2034-11-24', 'N')
     t.assert.strictEqual(d, '5')
   })
 
   it("should format '2002-02-3' as '7'", (t) => {
-    const d = dateFormat('2002-02-3', 'N')
+    const d = dateformat('2002-02-3', 'N')
     t.assert.strictEqual(d, '7')
   })
 
   it("should format '2002-02-4' as '1'", (t) => {
-    const d = dateFormat('2002-02-4', 'N')
+    const d = dateformat('2002-02-4', 'N')
     t.assert.strictEqual(d, '1')
   })
 })
diff --git a/test/dateformat/test_mask-o.js b/test/dateformat/test_mask-o.js
index e8d54e1..16413f1 100644
--- a/test/dateformat/test_mask-o.js
+++ b/test/dateformat/test_mask-o.js
@@ -1,10 +1,10 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'o'", function () {
   it('should get timezone for any date as something like [+-]XXXX', (t) => {
     const date = new Date()
-    const d = dateFormat(date, 'o')
+    const d = dateformat(date, 'o')
     t.assert.ok(d.match(/^[+-]\d{4}$/), d)
   })
 })
diff --git a/test/dateformat/test_mask-p.js b/test/dateformat/test_mask-p.js
index 0b75d03..4273b38 100644
--- a/test/dateformat/test_mask-p.js
+++ b/test/dateformat/test_mask-p.js
@@ -1,12 +1,12 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'p'", function () {
   it('should get timezone for any date as something like [+-]XX:XX', (t) => {
     const date = new Date()
-    const d = dateFormat(date, 'p')
+    const d = dateformat(date, 'p')
     t.assert.ok(d.match(/^[+-]\d{2}:\d{2}$/), d)
 
-    console.log(dateFormat(date, 'isoDateTime'))
+    console.log(dateformat(date, 'isoDateTime'))
   })
 })
diff --git a/test/dateformat/test_mask-s.js b/test/dateformat/test_mask-s.js
index 602ffe6..367ae36 100644
--- a/test/dateformat/test_mask-s.js
+++ b/test/dateformat/test_mask-s.js
@@ -1,21 +1,21 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 's'", function () {
   it("should format '1993-10-08T10:31:40.811' as '40'", (t) => {
     const date = new Date('1993-10-08T10:31:40.811')
-    const d = dateFormat(date, 's')
+    const d = dateformat(date, 's')
     t.assert.strictEqual(d, '40')
   })
 
   it("should format '2020-10-25T01:29:02.327' as '2'", (t) => {
     const date = new Date('2020-10-25T01:29:02.327')
-    const d = dateFormat(date, 's')
+    const d = dateformat(date, 's')
     t.assert.strictEqual(d, '2')
   })
 
   it("should format '2003-07-02T01:29:00.327' as '0'", (t) => {
-    const d = dateFormat('2003-07-02T01:29:00.327', 's')
+    const d = dateformat('2003-07-02T01:29:00.327', 's')
     t.assert.strictEqual(d, '0')
   })
 })
diff --git a/test/dateformat/test_mask-s_.js b/test/dateformat/test_mask-s_.js
index ae65c73..dec7bb3 100644
--- a/test/dateformat/test_mask-s_.js
+++ b/test/dateformat/test_mask-s_.js
@@ -1,31 +1,31 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'S'", function () {
   it("should format '1984-02-7' as 'th'", (t) => {
     const date = new Date('1984-02-7')
-    const d = dateFormat(date, 'S')
+    const d = dateformat(date, 'S')
     t.assert.strictEqual(d, 'th')
   })
 
   it("should format '2013-01-3' as 'rd'", (t) => {
     const date = new Date('2013-01-3')
-    const d = dateFormat(date, 'S')
+    const d = dateformat(date, 'S')
     t.assert.strictEqual(d, 'rd')
   })
 
   it("should format '2034-11-22' as 'nd'", (t) => {
-    const d = dateFormat('2034-11-22', 'S')
+    const d = dateformat('2034-11-22', 'S')
     t.assert.strictEqual(d, 'nd')
   })
 
   it("should format '2002-02-1' as 'st'", (t) => {
-    const d = dateFormat('2002-02-1', 'S')
+    const d = dateformat('2002-02-1', 'S')
     t.assert.strictEqual(d, 'st')
   })
 
   it("should format '2002-03-31' as 'st'", (t) => {
-    const d = dateFormat('2002-03-31', 'S')
+    const d = dateformat('2002-03-31', 'S')
     t.assert.strictEqual(d, 'st')
   })
 })
diff --git a/test/dateformat/test_mask-ss.js b/test/dateformat/test_mask-ss.js
index 77ec02c..fd2a738 100644
--- a/test/dateformat/test_mask-ss.js
+++ b/test/dateformat/test_mask-ss.js
@@ -1,26 +1,26 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'ss'", function () {
   it("should format '1876-03-22T23:08:02.429' as '02'", (t) => {
     const date = new Date('1876-03-22T23:08:02.429')
-    const d = dateFormat(date, 'ss')
+    const d = dateformat(date, 'ss')
     t.assert.strictEqual(d, '02')
   })
 
   it("should format '2013-12-11T05:34:35.350' as '35'", (t) => {
     const date = new Date('2013-12-11T05:34:35.350')
-    const d = dateFormat(date, 'ss')
+    const d = dateformat(date, 'ss')
     t.assert.strictEqual(d, '35')
   })
 
   it("should format '2020-08-29T00:32:00.101' as '00'", (t) => {
-    const d = dateFormat('2020-08-29T00:32:00.101', 'ss')
+    const d = dateformat('2020-08-29T00:32:00.101', 'ss')
     t.assert.strictEqual(d, '00')
   })
 
   it("should format '2020-09-22T07:04:09.358' as '09'", (t) => {
-    const d = dateFormat('2020-09-22T07:04:09.358', 'ss')
+    const d = dateformat('2020-09-22T07:04:09.358', 'ss')
     t.assert.strictEqual(d, '09')
   })
 })
diff --git a/test/dateformat/test_mask-t.js b/test/dateformat/test_mask-t.js
index 84e4d8f..4a18a9b 100644
--- a/test/dateformat/test_mask-t.js
+++ b/test/dateformat/test_mask-t.js
@@ -1,26 +1,26 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 't'", function () {
   it("should format '1876-03-22T23:08:02.429' as 'p'", (t) => {
     const date = new Date('1876-03-22T23:08:02.429')
-    const d = dateFormat(date, 't')
+    const d = dateformat(date, 't')
     t.assert.strictEqual(d, 'p')
   })
 
   it("should format '2013-12-11T05:34:35.350' as 'a'", (t) => {
     const date = new Date('2013-12-11T05:34:35.350')
-    const d = dateFormat(date, 't')
+    const d = dateformat(date, 't')
     t.assert.strictEqual(d, 'a')
   })
 
   it("should format '2020-08-29T00:32:00.101' as 'a'", (t) => {
-    const d = dateFormat('2020-08-29T00:32:00.101', 't')
+    const d = dateformat('2020-08-29T00:32:00.101', 't')
     t.assert.strictEqual(d, 'a')
   })
 
   it("should format '2020-09-22T23:04:09.358' as 'p'", (t) => {
-    const d = dateFormat('2020-09-22T23:04:09.358', 't')
+    const d = dateformat('2020-09-22T23:04:09.358', 't')
     t.assert.strictEqual(d, 'p')
   })
 })
diff --git a/test/dateformat/test_mask-t_.js b/test/dateformat/test_mask-t_.js
index 8c12795..6d24d49 100644
--- a/test/dateformat/test_mask-t_.js
+++ b/test/dateformat/test_mask-t_.js
@@ -1,26 +1,26 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'T'", function () {
   it("should format '1654-04-11T08:47:34.086' as 'A'", (t) => {
     const date = new Date('1654-04-11T08:47:34.086')
-    const d = dateFormat(date, 'T')
+    const d = dateformat(date, 'T')
     t.assert.strictEqual(d, 'A')
   })
 
   it("should format '2001-02-06T15:10:43.798' as 'P'", (t) => {
     const date = new Date('2001-02-06T15:10:43.798')
-    const d = dateFormat(date, 'T')
+    const d = dateformat(date, 'T')
     t.assert.strictEqual(d, 'P')
   })
 
   it("should format '1998-12-01T12:43:14.920' as 'A'", (t) => {
-    const d = dateFormat('2020-08-29T00:32:00.101', 'T')
+    const d = dateformat('2020-08-29T00:32:00.101', 'T')
     t.assert.strictEqual(d, 'A')
   })
 
   it("should format '2020-10-01T17:20:03.223' as 'p'", (t) => {
-    const d = dateFormat('2020-10-01T17:20:03.223', 'T')
+    const d = dateformat('2020-10-01T17:20:03.223', 'T')
     t.assert.strictEqual(d, 'P')
   })
 })
diff --git a/test/dateformat/test_mask-t_t_.js b/test/dateformat/test_mask-t_t_.js
index 58b0500..52e4ae8 100644
--- a/test/dateformat/test_mask-t_t_.js
+++ b/test/dateformat/test_mask-t_t_.js
@@ -1,26 +1,26 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'TT'", function () {
   it("should format '1876-04-23T07:35:20.830' as 'AM'", (t) => {
     const date = new Date('1876-04-23T07:35:20.830')
-    const d = dateFormat(date, 'TT')
+    const d = dateformat(date, 'TT')
     t.assert.strictEqual(d, 'AM')
   })
 
   it("should format '2018-04-27T18:50:35.567' as 'PM'", (t) => {
     const date = new Date('2018-04-27T18:50:35.567')
-    const d = dateFormat(date, 'TT')
+    const d = dateformat(date, 'TT')
     t.assert.strictEqual(d, 'PM')
   })
 
   it("should format '2032-05-07T06:45:41.382' as 'AM'", (t) => {
-    const d = dateFormat('2032-05-07T06:45:41.382', 'TT')
+    const d = dateformat('2032-05-07T06:45:41.382', 'TT')
     t.assert.strictEqual(d, 'AM')
   })
 
   it("should format '1976-11-25T19:44:08.918' as 'PM'", (t) => {
-    const d = dateFormat('1976-11-25T19:44:08.918', 'TT')
+    const d = dateformat('1976-11-25T19:44:08.918', 'TT')
     t.assert.strictEqual(d, 'PM')
   })
 })
diff --git a/test/dateformat/test_mask-tt.js b/test/dateformat/test_mask-tt.js
index 6c05703..a457ce2 100644
--- a/test/dateformat/test_mask-tt.js
+++ b/test/dateformat/test_mask-tt.js
@@ -1,26 +1,26 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'tt'", function () {
   it("should format '1876-03-22T23:08:02.429' as 'pm'", (t) => {
     const date = new Date('1876-03-22T23:08:02.429')
-    const d = dateFormat(date, 'tt')
+    const d = dateformat(date, 'tt')
     t.assert.strictEqual(d, 'pm')
   })
 
   it("should format '2013-12-11T05:34:35.350' as 'am'", (t) => {
     const date = new Date('2013-12-11T05:34:35.350')
-    const d = dateFormat(date, 'tt')
+    const d = dateformat(date, 'tt')
     t.assert.strictEqual(d, 'am')
   })
 
   it("should format '2020-08-29T00:32:00.101' as 'am'", (t) => {
-    const d = dateFormat('2020-08-29T00:32:00.101', 'tt')
+    const d = dateformat('2020-08-29T00:32:00.101', 'tt')
     t.assert.strictEqual(d, 'am')
   })
 
   it("should format '2020-09-22T23:04:09.358' as 'pm'", (t) => {
-    const d = dateFormat('2020-09-22T23:04:09.358', 'tt')
+    const d = dateformat('2020-09-22T23:04:09.358', 'tt')
     t.assert.strictEqual(d, 'pm')
   })
 })
diff --git a/test/dateformat/test_mask-w_.js b/test/dateformat/test_mask-w_.js
index 4583a69..1696553 100644
--- a/test/dateformat/test_mask-w_.js
+++ b/test/dateformat/test_mask-w_.js
@@ -1,26 +1,26 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'W'", function () {
   it("should format '1876-03-22' as '12'", (t) => {
     const date = new Date('1876-03-22')
-    const d = dateFormat(date, 'W')
+    const d = dateformat(date, 'W')
     t.assert.strictEqual(d, '12')
   })
 
   it("should format '2013-12-11' as '50'", (t) => {
     const date = new Date('2013-12-11')
-    const d = dateFormat(date, 'W')
+    const d = dateformat(date, 'W')
     t.assert.strictEqual(d, '50')
   })
 
   it("should format '2020-08-29' as '35'", (t) => {
-    const d = dateFormat('2020-08-29', 'W')
+    const d = dateformat('2020-08-29', 'W')
     t.assert.strictEqual(d, '35')
   })
 
   it("should format '2020-09-22' as '39'", (t) => {
-    const d = dateFormat('2020-09-22', 'W')
+    const d = dateformat('2020-09-22', 'W')
     t.assert.strictEqual(d, '39')
   })
 })
diff --git a/test/dateformat/test_mask-ww_.js b/test/dateformat/test_mask-ww_.js
index d789cc4..1b0d555 100644
--- a/test/dateformat/test_mask-ww_.js
+++ b/test/dateformat/test_mask-ww_.js
@@ -1,26 +1,26 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'WW'", function () {
   it("should format '1876-01-12' as '02'", (t) => {
     const date = new Date('1876-01-12')
-    const d = dateFormat(date, 'WW')
+    const d = dateformat(date, 'WW')
     t.assert.strictEqual(d, '02')
   })
 
   it("should format '2013-12-11' as '50'", (t) => {
     const date = new Date('2013-12-11')
-    const d = dateFormat(date, 'WW')
+    const d = dateformat(date, 'WW')
     t.assert.strictEqual(d, '50')
   })
 
   it("should format '2020-03-04' as '10'", (t) => {
-    const d = dateFormat('2020-03-04', 'WW')
+    const d = dateformat('2020-03-04', 'WW')
     t.assert.strictEqual(d, '10')
   })
 
   it("should format '2020-02-01' as '05'", (t) => {
-    const d = dateFormat('2020-02-01', 'WW')
+    const d = dateformat('2020-02-01', 'WW')
     t.assert.strictEqual(d, '05')
   })
 })
diff --git a/test/dateformat/test_mask-yy.js b/test/dateformat/test_mask-yy.js
index 12afa7c..4f70b84 100644
--- a/test/dateformat/test_mask-yy.js
+++ b/test/dateformat/test_mask-yy.js
@@ -1,28 +1,28 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'yy'", function () {
   it("should format '1789-11-12' as '89'", (t) => {
     const date = new Date('1789-11-12')
-    const d = dateFormat(date, 'yy')
+    const d = dateformat(date, 'yy')
     t.assert.strictEqual(d, '89')
   })
 
   it("should format '2089-10-2' as '89'", (t) => {
     const date = new Date('2089-10-2')
-    const d = dateFormat(date, 'yy')
+    const d = dateformat(date, 'yy')
     t.assert.strictEqual(d, '89')
   })
 
   it("should format '2000-02-7' as '00'", (t) => {
     const date = new Date('2000-02-7')
-    const d = dateFormat(date, 'yy')
+    const d = dateformat(date, 'yy')
     t.assert.strictEqual(d, '00')
   })
 
   it("should format '1999-11-27' as '99'", (t) => {
     const date = new Date('1999-11-27')
-    const d = dateFormat(date, 'yy')
+    const d = dateformat(date, 'yy')
     t.assert.strictEqual(d, '99')
   })
 })
diff --git a/test/dateformat/test_mask-yyyy.js b/test/dateformat/test_mask-yyyy.js
index 709be54..ffc0885 100644
--- a/test/dateformat/test_mask-yyyy.js
+++ b/test/dateformat/test_mask-yyyy.js
@@ -1,34 +1,34 @@
 const { describe, it } = require('node:test')
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe("Mask: 'yyyy'", function () {
   it("should format '1992-10-6' as '1992'", (t) => {
     const date = new Date('1992-10-6')
-    const d = dateFormat(date, 'yyyy')
+    const d = dateformat(date, 'yyyy')
     t.assert.strictEqual(d, '1992')
   })
 
   it("should format '2078-02-11' as '2078'", (t) => {
     const date = new Date('2078-02-11')
-    const d = dateFormat(date, 'yyyy')
+    const d = dateformat(date, 'yyyy')
     t.assert.strictEqual(d, '2078')
   })
 
   it("should format '1763-12-02' as '1763'", (t) => {
     const date = new Date('1763-12-02')
-    const d = dateFormat(date, 'yyyy')
+    const d = dateformat(date, 'yyyy')
     t.assert.strictEqual(d, '1763')
   })
 
   it("should format '0999-01-01' as '0999'", (t) => {
     const date = new Date('0999-01-01')
-    const d = dateFormat(date, 'yyyy')
+    const d = dateformat(date, 'yyyy')
     t.assert.strictEqual(d, '0999')
   })
 
   it("should format '0002-12-11' as '0002'", (t) => {
     const date = new Date('0002-12-11')
-    const d = dateFormat(date, 'yyyy')
+    const d = dateformat(date, 'yyyy')
     t.assert.strictEqual(d, '0002')
   })
 })
diff --git a/test/dateformat/test_quotes.js b/test/dateformat/test_quotes.js
index 063060b..598453a 100644
--- a/test/dateformat/test_quotes.js
+++ b/test/dateformat/test_quotes.js
@@ -1,16 +1,16 @@
 const { describe, it } = require('node:test')
 
-const { dateFormat } = require('./../../index.js')
+const { dateformat } = require('./../../index.js')
 
 describe('quoted substrings', function () {
   const az = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
   it('should not format single quoted substrings removing quotes', function (t) {
-    const result = dateFormat(new Date(), "'" + az + "'")
+    const result = dateformat(new Date(), "'" + az + "'")
     t.assert.strictEqual(result, az)
   })
 
   it('should not format double quoted substrings removing quotes', function (t) {
-    const result = dateFormat(new Date(), '"' + az + '"')
+    const result = dateformat(new Date(), '"' + az + '"')
     t.assert.strictEqual(result, az)
   })
 })
diff --git a/test/dateformat/test_threedays.js b/test/dateformat/test_threedays.js
index 615cf07..cc962a1 100644
--- a/test/dateformat/test_threedays.js
+++ b/test/dateformat/test_threedays.js
@@ -1,6 +1,6 @@
 const { describe, it, beforeEach } = require('node:test')
 
-const { dateFormat } = require('../../index.js')
+const { dateformat } = require('../../index.js')
 
 const dayNamesShort = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat']
 const dayNamesLong = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday']
@@ -13,64 +13,64 @@ describe('threeDays', function () {
   })
   it('should return "Yesterday" (Today - 1 day)', (t) => {
     date.setDate(date.getDate() - 1)
-    DDDD = dateFormat(date, 'DDDD')
+    DDDD = dateformat(date, 'DDDD')
     t.assert.strictEqual(DDDD, 'Yesterday')
   })
   it('should return "Ysd" (Today - 1 day)', (t) => {
     date.setDate(date.getDate() - 1)
-    DDD = dateFormat(date, 'DDD')
+    DDD = dateformat(date, 'DDD')
     t.assert.strictEqual(DDD, 'Ysd')
   })
   it('should return "Today" (Today)', (t) => {
-    DDDD = dateFormat(date, 'DDDD')
+    DDDD = dateformat(date, 'DDDD')
     t.assert.strictEqual(DDDD, 'Today')
   })
   it('should return "Tdy" (Today)', (t) => {
-    DDD = dateFormat(date, 'DDD')
+    DDD = dateformat(date, 'DDD')
     t.assert.strictEqual(DDD, 'Tdy')
   })
   it('should return "Tomorrow" (Today + 1 day)', (t) => {
     date.setDate(date.getDate() + 1)
-    DDDD = dateFormat(date, 'DDDD')
+    DDDD = dateformat(date, 'DDDD')
     t.assert.strictEqual(DDDD, 'Tomorrow')
   })
   it('should return "Tmw" (Today + 1 day)', (t) => {
     date.setDate(date.getDate() + 1)
-    DDD = dateFormat(date, 'DDD')
+    DDD = dateformat(date, 'DDD')
     t.assert.strictEqual(DDD, 'Tmw')
   })
   it('should not return "Yesterday", "Today", "Tomorrow", "Ysd", "Tdy", or "Tmw" (Today - 2 days)', (t) => {
     date.setDate(date.getDate() - 2)
-    DDD = dateFormat(date, 'DDD')
-    DDDD = dateFormat(date, 'DDDD')
+    DDD = dateformat(date, 'DDD')
+    DDDD = dateformat(date, 'DDDD')
     t.assert.strictEqual(threeDays.indexOf(DDD), -1)
     t.assert.strictEqual(threeDays.indexOf(DDDD), -1)
   })
   it('should not return "Yesterday", "Today" or "Tomorrow", "Ysd", "Tdy", or "Tmw" (Today + 2 days)', (t) => {
     date.setDate(date.getDate() + 2)
-    DDD = dateFormat(date, 'DDD')
-    DDDD = dateFormat(date, 'DDDD')
+    DDD = dateformat(date, 'DDD')
+    DDDD = dateformat(date, 'DDDD')
     t.assert.strictEqual(threeDays.indexOf(DDD), -1)
     t.assert.strictEqual(threeDays.indexOf(DDDD), -1)
   })
   it('should return short day name (Today - 2 days)', (t) => {
     date.setDate(date.getDate() - 2)
-    DDD = dateFormat(date, 'DDD')
+    DDD = dateformat(date, 'DDD')
     t.assert.notStrictEqual(dayNamesShort.indexOf(DDD), -1)
   })
   it('should return short day name (Today + 2 days)', (t) => {
     date.setDate(date.getDate() + 2)
-    DDD = dateFormat(date, 'DDD')
+    DDD = dateformat(date, 'DDD')
     t.assert.notStrictEqual(dayNamesShort.indexOf(DDD), -1)
   })
   it('should return long day name (Today - 2 days)', (t) => {
     date.setDate(date.getDate() - 2)
-    DDDD = dateFormat(date, 'DDDD')
+    DDDD = dateformat(date, 'DDDD')
     t.assert.notStrictEqual(dayNamesLong.indexOf(DDDD), -1)
   })
   it('should return short day name (Today + 2 days)', (t) => {
     date.setDate(date.getDate() + 2)
-    DDDD = dateFormat(date, 'DDDD')
+    DDDD = dateformat(date, 'DDDD')
     t.assert.notStrictEqual(dayNamesLong.indexOf(DDDD), -1)
   })
 })