From 6232e8ddb83538c141e05fbd5965770662659496 Mon Sep 17 00:00:00 2001
From: Marc Bachmann <marc.brookman@gmail.com>
Date: Wed, 27 May 2015 02:04:45 +0200
Subject: [PATCH] Support /- and nested properties

---
 jsonpointer.js | 62 ++++++++++++++++++++++++++++++++++----------------
 test.js        | 18 +++++++++++----
 2 files changed, 57 insertions(+), 23 deletions(-)

diff --git a/jsonpointer.js b/jsonpointer.js
index 006f85e..8fb3397 100644
--- a/jsonpointer.js
+++ b/jsonpointer.js
@@ -11,34 +11,51 @@ var untilde = function(str) {
 }
 
 var traverse = function(obj, pointer, value) {
-  // assert(isArray(pointer))
   var part = untilde(pointer.shift());
-  if(!obj.hasOwnProperty(part)) {
-    return null;
+  var isJustReading = arguments.length === 2;
+
+  if (obj[part] == null) {
+    if (isJustReading) return null;
+
+    // support setting of /-
+    if (part === '-' && obj instanceof Array) {
+      part = obj.length;
+    }
+
+    // support nested objects/array when setting values
+    var nextPart = pointer[0];
+    if (nextPart === '-' || !isNaN(nextPart)) {
+      obj[part] = [];
+    } else if (nextPart) {
+      obj[part] = {};
+    }
   }
-  if(pointer.length !== 0) { // keep traversin!
-    return traverse(obj[part], pointer, value);
+
+  // keep traversing
+  if (pointer.length !== 0) {
+    if (isJustReading) {
+      return traverse(obj[part], pointer);
+    } else {
+      return traverse(obj[part], pointer, value);
+    }
   }
+
   // we're done
-  if(typeof value === "undefined") {
-    // just reading
+  if (isJustReading) {
     return obj[part];
   }
+
   // set new value, return old value
-  var old_value = obj[part];
-  if(value === null) {
+  var oldValue = obj[part];
+  if (value === null) {
     delete obj[part];
   } else {
     obj[part] = value;
   }
-  return old_value;
+  return oldValue;
 }
 
-var validate_input = function(obj, pointer) {
-  if(typeof obj !== "object") {
-    throw new Error("Invalid input object.");
-  }
-
+var compilePointer = function(pointer) {
   if(pointer === "") {
     return [];
   }
@@ -47,15 +64,22 @@ var validate_input = function(obj, pointer) {
     throw new Error("Invalid JSON pointer.");
   }
 
-  pointer = pointer.split("/");
-  var first = pointer.shift();
-  if (first !== "") {
-    throw new Error("Invalid JSON pointer.");
+  if (!(pointer instanceof Array)) {
+    pointer = pointer.split("/");
+    if (pointer.shift() !== "") throw new Error("Invalid JSON pointer.")
   }
 
   return pointer;
 }
 
+var validate_input = function(obj, pointer) {
+  if(typeof obj !== "object") {
+    throw new Error("Invalid input object.");
+  }
+
+  return compilePointer(pointer);
+}
+
 var get = function(obj, pointer) {
   pointer = validate_input(obj, pointer);
   if (pointer.length === 0) {
diff --git a/test.js b/test.js
index 1c67d7f..a596843 100644
--- a/test.js
+++ b/test.js
@@ -1,5 +1,5 @@
-var assert = require("assert");
-var jsonpointer = require("./jsonpointer");
+var assert = require('assert');
+var jsonpointer = require('./jsonpointer');
 
 var obj = {
   a: 1,
@@ -24,6 +24,16 @@ assert.equal(jsonpointer.set(obj, "/d/e/0/a", 4), 3);
 assert.equal(jsonpointer.set(obj, "/d/e/1/b", 5), 4);
 assert.equal(jsonpointer.set(obj, "/d/e/2/c", 6), 5);
 
+// set nested properties
+assert.equal(jsonpointer.set(obj, "/f/g/h/i", 6), undefined);
+assert.equal(jsonpointer.get(obj, "/f/g/h/i"), 6);
+
+// set an array
+assert.equal(jsonpointer.set(obj, "/f/g/h/foo/-", 'test'), undefined);
+arr = jsonpointer.get(obj, "/f/g/h/foo")
+assert(Array.isArray(arr), 'set /- creates an array.');
+assert.equal(arr[0], 'test');
+
 assert.equal(jsonpointer.get(obj, "/a"), 2);
 assert.equal(jsonpointer.get(obj, "/b/c"), 3);
 assert.equal(jsonpointer.get(obj, "/d/e/0/a"), 4);
@@ -62,8 +72,8 @@ assert.equal(jsonpointer.get(complexKeys, "/~1"), null);
 var ary = [ "zero", "one", "two" ];
 assert.equal(jsonpointer.get(ary, "/01"), null);
 
-//assert.equal(jsonpointer.set(ary, "/-", "three"), null);
-//assert.equal(ary[3], "three");
+assert.equal(jsonpointer.set(ary, "/-", "three"), null);
+assert.equal(ary[3], "three");
 
 // Examples from the draft:
 var example = {