deep_cyclic_copy.js 2.5 KB

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  1. 'use strict';
  2. Object.defineProperty(exports, "__esModule", {
  3. value: true
  4. });
  5. exports.default = deepCyclicCopy;
  6. /**
  7. * Copyright (c) 2017-present, Facebook, Inc. All rights reserved.
  8. *
  9. * This source code is licensed under the MIT license found in the
  10. * LICENSE file in the root directory of this source tree.
  11. *
  12. *
  13. */
  14. const EMPTY = new Set();
  15. // Node 6 does not have gOPDs, so we define a simple polyfill for it.
  16. if (!Object.getOwnPropertyDescriptors) {
  17. // $FlowFixMe: polyfill
  18. Object.getOwnPropertyDescriptors = obj => {
  19. const list = {};
  20. Object.getOwnPropertyNames(obj).concat(Object.getOwnPropertySymbols(obj))
  21. // $FlowFixMe: assignment with a Symbol is OK.
  22. .forEach(key => list[key] = Object.getOwnPropertyDescriptor(obj, key));
  23. return list;
  24. };
  25. }
  26. function deepCyclicCopy(value) {
  27. let options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : { blacklist: EMPTY, keepPrototype: false };
  28. let cycles = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : new WeakMap();
  29. if (typeof value !== 'object' || value === null) {
  30. return value;
  31. } else if (cycles.has(value)) {
  32. return cycles.get(value);
  33. } else if (Array.isArray(value)) {
  34. return deepCyclicCopyArray(value, options, cycles);
  35. } else {
  36. return deepCyclicCopyObject(value, options, cycles);
  37. }
  38. }
  39. function deepCyclicCopyObject(object, options, cycles) {
  40. const newObject = options.keepPrototype ? Object.create(Object.getPrototypeOf(object)) : {};
  41. // $FlowFixMe: Object.getOwnPropertyDescriptors is polyfilled above.
  42. const descriptors = Object.getOwnPropertyDescriptors(object);
  43. cycles.set(object, newObject);
  44. Object.keys(descriptors).forEach(key => {
  45. if (options.blacklist && options.blacklist.has(key)) {
  46. delete descriptors[key];
  47. return;
  48. }
  49. const descriptor = descriptors[key];
  50. if (typeof descriptor.value !== 'undefined') {
  51. descriptor.value = deepCyclicCopy(descriptor.value, { blacklist: EMPTY, keepPrototype: options.keepPrototype }, cycles);
  52. }
  53. descriptor.configurable = true;
  54. });
  55. return Object.defineProperties(newObject, descriptors);
  56. }
  57. function deepCyclicCopyArray(array, options, cycles) {
  58. const newArray = options.keepPrototype ? // $FlowFixMe: getPrototypeOf an array is OK.
  59. new (Object.getPrototypeOf(array).constructor)(array.length) : [];
  60. const length = array.length;
  61. cycles.set(array, newArray);
  62. for (let i = 0; i < length; i++) {
  63. newArray[i] = deepCyclicCopy(array[i], { blacklist: EMPTY, keepPrototype: options.keepPrototype }, cycles);
  64. }
  65. return newArray;
  66. }