Verify that JSON.stringify passes keys as strings when calling toJSON or the replacer function. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". Test Replacer Function PASS typeof globalKey is "string" PASS globalKey is "" PASS typeof globalValue is "object" PASS globalValue instanceof Array is true PASS globalValue.length is 1 PASS globalValue[0] is 42 PASS typeof globalKey is "string" PASS globalKey is "0" PASS typeof globalValue is "number" PASS globalValue is 42 PASS JSON.stringify([42], replacer) is "[5]" Test toJSON Function PASS toJSONArrayHelperCallCounter is 0 PASS globalThis === testArray is true PASS typeof globalKey is "string" PASS globalKey is "" PASS toJSONArrayHelperCallCounter is 1 PASS globalThis === testObject is true PASS typeof globalKey is "string" PASS globalKey is "0" PASS JSON.stringify(testArray) is "[true]" PASS successfullyParsed is true TEST COMPLETE