From 0cc66872b9ab200a11f8ccc7b6363a45b779785f Mon Sep 17 00:00:00 2001
From: Davis Vaughan <davis@posit.co>
Date: Wed, 6 Aug 2025 10:48:37 -0400
Subject: [PATCH] Expose `is_array_insertion`

---
 R/modify.R      | 29 ++++++++++++++++++++++++-----
 man/jsonedit.Rd | 22 +++++++++++++++++++---
 2 files changed, 43 insertions(+), 8 deletions(-)

diff --git a/R/modify.R b/R/modify.R
index eabcc45..c92f789 100644
--- a/R/modify.R
+++ b/R/modify.R
@@ -9,6 +9,8 @@
 #' @param json_path character vector or list specifies which element to modify.
 #' @param value new value. Wrap in [V8::JS()] to specify literal JavaScript value.
 #' Use `NULL` to delete the field.
+#' @param is_array_insertion whether to treat the modification as an insertion
+#' into an array or not. Has no effect when `json_path` doesn't target an array.
 #' @examples
 #' # update field on existing settings.json
 #' json_modify_file('settings.json', c('[r]', 'editor.formatOnSave'), TRUE)
@@ -19,14 +21,25 @@
 #' json_modify_file('test.json', c("foo", "bar"), 1:3)
 #' json_modify_file('test.json', c("foo", "baz"), TRUE)
 #' json_modify_file('test.json', list("foo", "bar", 1), 9999)
-json_modify_text <- function(text, json_path, value, spaces = 4) {
+#' json_modify_file('test.json', list("foo", "bar", 1), 9998, is_array_insertion = TRUE)
+json_modify_text <- function(
+  text,
+  json_path,
+  value,
+  spaces = 4,
+  is_array_insertion = FALSE
+) {
   stopifnot(is.character(text))
   text <- paste(text, collapse = '\n')
   if (is.null(value)) {
     value <- V8::JS('undefined')
   }
-  opts <- if (length(spaces)) {
-    list(formattingOptions = list(insertSpaces = spaces > 0, tabSize = spaces))
+  opts <- list(isArrayInsertion = is_array_insertion)
+  if (length(spaces)) {
+    opts[["formattingOptions"]] <- list(
+      insertSpaces = spaces > 0,
+      tabSize = spaces
+    )
   }
   if (!is.null(json_parse_errors(text))) {
     stop("Can't modify when there are existing parse errors.")
@@ -37,13 +50,19 @@ json_modify_text <- function(text, json_path, value, spaces = 4) {
 #' @export
 #' @rdname jsonedit
 #' @param file path to file on disk. Will be created if it does not exist.
-json_modify_file <- function(file, json_path, value, spaces = 4) {
+json_modify_file <- function(
+  file,
+  json_path,
+  value,
+  spaces = 4,
+  is_array_insertion = FALSE
+) {
   text <- if (file.exists(file)) {
     rawToChar(readBin(file, raw(), file.info(file)$size))
   } else {
     "{}"
   }
-  out <- json_modify_text(text, json_path, value, spaces)
+  out <- json_modify_text(text, json_path, value, spaces, is_array_insertion)
   writeLines(out, file)
 }
 
diff --git a/man/jsonedit.Rd b/man/jsonedit.Rd
index 2ec13a0..9a9feeb 100644
--- a/man/jsonedit.Rd
+++ b/man/jsonedit.Rd
@@ -7,9 +7,21 @@
 \alias{json_format_file}
 \title{Modify a JSON file or string}
 \usage{
-json_modify_text(text, json_path, value, spaces = 4)
-
-json_modify_file(file, json_path, value, spaces = 4)
+json_modify_text(
+  text,
+  json_path,
+  value,
+  spaces = 4,
+  is_array_insertion = FALSE
+)
+
+json_modify_file(
+  file,
+  json_path,
+  value,
+  spaces = 4,
+  is_array_insertion = FALSE
+)
 
 json_format_text(text, spaces = 4)
 
@@ -25,6 +37,9 @@ Use `NULL` to delete the field.}
 
 \item{spaces}{number of spaces to indent. Use 0 for tabs.}
 
+\item{is_array_insertion}{whether to treat the modification as an insertion
+into an array or not. Has no effect when `json_path` doesn't target an array.}
+
 \item{file}{path to file on disk. Will be created if it does not exist.}
 }
 \description{
@@ -41,4 +56,5 @@ json_modify_file('test.json', 'title', "This is a test")
 json_modify_file('test.json', c("foo", "bar"), 1:3)
 json_modify_file('test.json', c("foo", "baz"), TRUE)
 json_modify_file('test.json', list("foo", "bar", 1), 9999)
+json_modify_file('test.json', list("foo", "bar", 1), 9998, is_array_insertion = TRUE)
 }