core-js/modules/es.json.stringify.js

Standard library

'use strict';
var $ = require('../internals/export');
var getBuiltIn = require('../internals/get-built-in');
var apply = require('../internals/function-apply');
var call = require('../internals/function-call');
var uncurryThis = require('../internals/function-uncurry-this');
var fails = require('../internals/fails');
var isArray = require('../internals/is-array');
var isCallable = require('../internals/is-callable');
var isRawJSON = require('../internals/is-raw-json');
var isSymbol = require('../internals/is-symbol');
var classof = require('../internals/classof-raw');
var toString = require('../internals/to-string');
var arraySlice = require('../internals/array-slice');
var parseJSONString = require('../internals/parse-json-string');
var uid = require('../internals/uid');
var NATIVE_SYMBOL = require('../internals/symbol-constructor-detection');
var NATIVE_RAW_JSON = require('../internals/native-raw-json');

var $String = String;
var $stringify = getBuiltIn('JSON', 'stringify');
var exec = uncurryThis(/./.exec);
var charAt = uncurryThis(''.charAt);
var charCodeAt = uncurryThis(''.charCodeAt);
var replace = uncurryThis(''.replace);
var slice = uncurryThis(''.slice);
var push = uncurryThis([].push);
var numberToString = uncurryThis(1.1.toString);

var surrogates = /[\uD800-\uDFFF]/g;
var lowSurrogates = /^[\uD800-\uDBFF]$/;
var hiSurrogates = /^[\uDC00-\uDFFF]$/;

var MARK = uid();
var MARK_LENGTH = MARK.length;

var WRONG_SYMBOLS_CONVERSION = !NATIVE_SYMBOL || fails(function () {
  var symbol = getBuiltIn('Symbol')('stringify detection');
  // MS Edge converts symbol values to JSON as {}
  return $stringify([symbol]) !== '[null]'
    // WebKit converts symbol values to JSON as null
    || $stringify({ a: symbol }) !== '{}'
    // V8 throws on boxed symbols
    || $stringify(Object(symbol)) !== '{}';
});

// https://github.com/tc39/proposal-well-formed-stringify
var ILL_FORMED_UNICODE = fails(function () {
  return $stringify('\uDF06\uD834') !== '"\\udf06\\ud834"'
    || $stringify('\uDEAD') !== '"\\udead"';
});

var stringifyWithProperSymbolsConversion = WRONG_SYMBOLS_CONVERSION ? function (it, replacer) {
  var args = arraySlice(arguments);
  var $replacer = getReplacerFunction(replacer);
  if (!isCallable($replacer) && (it === undefined || isSymbol(it))) return; // IE8 returns string on undefined
  args[1] = function (key, value) {
    // some old implementations (like WebKit) could pass numbers as keys
    if (isCallable($replacer)) value = call($replacer, this, $String(key), value);
    if (!isSymbol(value)) return value;
  };
  return apply($stringify, null, args);
} : $stringify;

var fixIllFormedJSON = function (match, offset, string) {
  var prev = charAt(string, offset - 1);
  var next = charAt(string, offset + 1);
  if ((exec(lowSurrogates, match) && !exec(hiSurrogates, next)) || (exec(hiSurrogates, match) && !exec(lowSurrogates, prev))) {
    return '\\u' + numberToString(charCodeAt(match, 0), 16);
  } return match;
};

var getReplacerFunction = function (replacer) {
  if (isCallable(replacer)) return replacer;
  if (!isArray(replacer)) return;
  var rawLength = replacer.length;
  var keys = [];
  for (var i = 0; i < rawLength; i++) {
    var element = replacer[i];
    if (typeof element == 'string') push(keys, element);
    else if (typeof element == 'number' || classof(element) === 'Number' || classof(element) === 'String') push(keys, toString(element));
  }
  var keysLength = keys.length;
  var root = true;
  return function (key, value) {
    if (root) {
      root = false;
      return value;
    }
    if (isArray(this)) return value;
    for (var j = 0; j < keysLength; j++) if (keys[j] === key) return value;
  };
};

// `JSON.stringify` method
// https://tc39.es/ecma262/#sec-json.stringify
// https://github.com/tc39/proposal-json-parse-with-source
if ($stringify) $({ target: 'JSON', stat: true, arity: 3, forced: WRONG_SYMBOLS_CONVERSION || ILL_FORMED_UNICODE || !NATIVE_RAW_JSON }, {
  stringify: function stringify(text, replacer, space) {
    var replacerFunction = getReplacerFunction(replacer);
    var rawStrings = [];

    var json = stringifyWithProperSymbolsConversion(text, function (key, value) {
      // some old implementations (like WebKit) could pass numbers as keys
      var v = isCallable(replacerFunction) ? call(replacerFunction, this, $String(key), value) : value;
      return !NATIVE_RAW_JSON && isRawJSON(v) ? MARK + (push(rawStrings, v.rawJSON) - 1) : v;
    }, space);

    if (typeof json != 'string') return json;

    if (ILL_FORMED_UNICODE) json = replace(json, surrogates, fixIllFormedJSON);

    if (NATIVE_RAW_JSON) return json;

    var result = '';
    var length = json.length;

    for (var i = 0; i < length; i++) {
      var chr = charAt(json, i);
      if (chr === '"') {
        var end = parseJSONString(json, ++i).end - 1;
        var string = slice(json, i, end);
        result += slice(string, 0, MARK_LENGTH) === MARK
          ? rawStrings[slice(string, MARK_LENGTH)]
          : '"' + string + '"';
        i = end;
      } else result += chr;
    }

    return result;
  }
});