feat: #125 strip leading commas in objects and arrays

josdejong · May 15, 2024 · 0ee8597 · 0ee8597
1 parent 019e509
commit 0ee8597
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Showing 3 changed files with 34 additions and 0 deletions.
diff --git a/src/index.test.ts b/src/index.test.ts
@@ -347,6 +347,20 @@ describe.each(implementations)('jsonrepair [$name]', ({ jsonrepair }) => {
       expect(jsonrepair('\\"hello"')).toBe('"hello"')
     })
 
+    test('should strip a leading comma from an array', () => {
+      expect(jsonrepair('[,1,2,3]')).toBe('[1,2,3]')
+      expect(jsonrepair('[/* a */,/* b */1,2,3]')).toBe('[1,2,3]')
+      expect(jsonrepair('[, 1,2,3]')).toBe('[ 1,2,3]')
+      expect(jsonrepair('[ , 1,2,3]')).toBe('[  1,2,3]')
+    })
+
+    test('should strip a leading comma from an object', () => {
+      expect(jsonrepair('{,"message": "hi"}')).toBe('{"message": "hi"}')
+      expect(jsonrepair('{/* a */,/* b */"message": "hi"}')).toBe('{"message": "hi"}')
+      expect(jsonrepair('{ ,"message": "hi"}')).toBe('{ "message": "hi"}')
+      expect(jsonrepair('{, "message": "hi"}')).toBe('{ "message": "hi"}')
+    })
+
     test('should strip trailing commas from an array', () => {
       expect(jsonrepair('[1,2,3,]')).toBe('[1,2,3]')
       expect(jsonrepair('[1,2,3,\n]')).toBe('[1,2,3\n]')

diff --git a/src/regular/jsonrepair.ts b/src/regular/jsonrepair.ts
@@ -248,6 +248,11 @@ export function jsonrepair(text: string): string {
       i++
       parseWhitespaceAndSkipComments()
 
+      // repair: skip leading comma like in {, message: "hi"}
+      if (skipCharacter(codeComma)) {
+        parseWhitespaceAndSkipComments()
+      }
+
       let initial = true
       while (i < text.length && text.charCodeAt(i) !== codeClosingBrace) {
         let processedComma
@@ -327,6 +332,11 @@ export function jsonrepair(text: string): string {
       i++
       parseWhitespaceAndSkipComments()
 
+      // repair: skip leading comma like in [,1,2,3]
+      if (skipCharacter(codeComma)) {
+        parseWhitespaceAndSkipComments()
+      }
+
       let initial = true
       while (i < text.length && text.charCodeAt(i) !== codeClosingBracket) {
         if (!initial) {

diff --git a/src/streaming/core.ts b/src/streaming/core.ts
@@ -206,6 +206,11 @@ export function jsonrepairCore({
   function parseObjectStart(): boolean {
     if (parseCharacter(codeOpeningBrace)) {
       parseWhitespaceAndSkipComments()
+
+      if (skipCharacter(codeComma)) {
+        parseWhitespaceAndSkipComments()
+      }
+
       if (parseCharacter(codeClosingBrace)) {
         return stack.update(Caret.afterValue)
       }
@@ -219,6 +224,11 @@ export function jsonrepairCore({
   function parseArrayStart(): boolean {
     if (parseCharacter(codeOpeningBracket)) {
       parseWhitespaceAndSkipComments()
+
+      if (skipCharacter(codeComma)) {
+        parseWhitespaceAndSkipComments()
+      }
+
       if (parseCharacter(codeClosingBracket)) {
         return stack.update(Caret.afterValue)
       }