fix: toJSON function receiving array keys as number instead of string

Author: BridgeAR

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## v2.4.3
 
+- Fixed toJSON function receiving array keys as number instead of string
 - Fixed replacer function receiving array keys as number instead of string
 - Fixed replacer function not being called for TypedArray entries
 - Improved performance to escape long strings that contain characters that need escaping

index.js

@@ -322,11 +322,11 @@ function configure (options) {
           const maximumValuesToStringify = Math.min(value.length, maximumBreadth)
           let i = 0
           for (; i < maximumValuesToStringify - 1; i++) {
-            const tmp = stringifyArrayReplacer(i, value[i], stack, replacer, spacer, indentation)
+            const tmp = stringifyArrayReplacer(String(i), value[i], stack, replacer, spacer, indentation)
             res += tmp !== undefined ? tmp : 'null'
             res += join
           }
-          const tmp = stringifyArrayReplacer(i, value[i], stack, replacer, spacer, indentation)
+          const tmp = stringifyArrayReplacer(String(i), value[i], stack, replacer, spacer, indentation)
           res += tmp !== undefined ? tmp : 'null'
           if (value.length - 1 > maximumBreadth) {
             const removedKeys = value.length - maximumBreadth - 1
@@ -412,11 +412,11 @@ function configure (options) {
           const maximumValuesToStringify = Math.min(value.length, maximumBreadth)
           let i = 0
           for (; i < maximumValuesToStringify - 1; i++) {
-            const tmp = stringifyIndent(i, value[i], stack, spacer, indentation)
+            const tmp = stringifyIndent(String(i), value[i], stack, spacer, indentation)
             res += tmp !== undefined ? tmp : 'null'
             res += join
           }
-          const tmp = stringifyIndent(i, value[i], stack, spacer, indentation)
+          const tmp = stringifyIndent(String(i), value[i], stack, spacer, indentation)
           res += tmp !== undefined ? tmp : 'null'
           if (value.length - 1 > maximumBreadth) {
             const removedKeys = value.length - maximumBreadth - 1
@@ -520,11 +520,11 @@ function configure (options) {
           const maximumValuesToStringify = Math.min(value.length, maximumBreadth)
           let i = 0
           for (; i < maximumValuesToStringify - 1; i++) {
-            const tmp = stringifySimple(i, value[i], stack)
+            const tmp = stringifySimple(String(i), value[i], stack)
             res += tmp !== undefined ? tmp : 'null'
             res += ','
           }
-          const tmp = stringifySimple(i, value[i], stack)
+          const tmp = stringifySimple(String(i), value[i], stack)
           res += tmp !== undefined ? tmp : 'null'
           if (value.length - 1 > maximumBreadth) {
             const removedKeys = value.length - maximumBreadth - 1

test.js

@@ -2,6 +2,32 @@ const { test } = require('tap')
 const { stringify } = require('./index.js')
 const clone = require('clone')
 
+test('toJSON receives array keys as string', function (assert) {
+  const object = [{
+    toJSON (key) {
+      assert.equal(key, '0')
+      return 42
+    }
+  }]
+
+  const expected = JSON.stringify(object)
+
+  let actual = stringify(object)
+  assert.equal(actual, expected)
+
+  actual = stringify(object, ['0'])
+  assert.equal(actual, expected)
+
+  // @ts-expect-error
+  actual = stringify(object, (key, value) => value)
+  assert.equal(actual, expected)
+
+  actual = stringify(object, null, 2)
+  assert.equal(actual, '[\n  42\n]')
+
+  assert.end()
+})
+
 test('circular reference to root', function (assert) {
   const fixture = { name: 'Tywin Lannister' }
   fixture.circle = fixture