src/immutable_support.js

  1. import { forEach } from 'underscore';
  2. import { at_maybe, cloneImpl } from '../src-cjs/constants.js';
  4. function ImmutableMixin({spliceOutWithDelete}) {
  5.   return {
  6.     [at_maybe]: function (key) {
  7.       return this.has(key) ? {just: this.get(key)} : {};
  8.     },
  9.     [cloneImpl]: function ({pop, set, spliceOut}) {
  10.       /* istanbul ignore next: unsupported */
  11.       if (pop) {
  12.         return this.pop();
  13.       }
  14.       if (set) {
  15.         return this.set(...set);
  16.       }
  17.       if (spliceOut) {
  18.         return spliceOutWithDelete ? this.delete(spliceOut) : this.set(spliceOut, undefined);
  19.       }
  20.       /* istanbul ignore next: no change requested */
  21.       return this;
  22.     },
  23.   };
  24. }
  26. /**
  27.  * @function module:natural-lenses#polyfillImmutable
  28.  * @summary Add lensing support methods to an Immutable type
  29.  * @param {Function} containerType  Target container type for support
  30.  *
  31.  * @description
  32.  * Adds mixin methods for supporting lenses to the given Immutable container
  33.  * type.
  34.  */
  35. function polyfillImmutable(containerType) {
  36.   const isList = containerType.isList;
  37.   const proto = containerType.prototype,
  38.     mixins = ImmutableMixin({spliceOutWithDelete: !isList});
  39.   forEach(
  40.     Object.getOwnPropertySymbols(mixins),
  41.     (name) => {
  42.       if (!proto.hasOwnProperty(name)) {
  43.         Object.defineProperty(proto, name, {
  44.           enumerable: false,
  45.           configurable: true,
  46.           writable: true,
  47.           value: mixins[name],
  48.         });
  49.       }
  50.     }
  51.   )
  52. }
  54. export { polyfillImmutable };