| 'use strict'; |
| |
| Object.defineProperty(exports, '__esModule', { |
| value: true, |
| }); |
| exports.keyMap = keyMap; |
| |
| /** |
| * Creates a keyed JS object from an array, given a function to produce the keys |
| * for each value in the array. |
| * |
| * This provides a convenient lookup for the array items if the key function |
| * produces unique results. |
| * @internal |
| * @example |
| * ```ts |
| * const phoneBook = [ |
| * { name: 'Jon', num: '555-1234' }, |
| * { name: 'Jenny', num: '867-5309' }, |
| * ]; |
| * |
| * const entriesByName = keyMap(phoneBook, (entry) => entry.name); |
| * |
| * Object.keys(entriesByName); // => ['Jon', 'Jenny'] |
| * entriesByName['Jenny']; // => { name: 'Jenny', num: '867-5309' } |
| * ``` |
| */ |
| function keyMap(list, keyFn) { |
| const result = Object.create(null); |
| |
| for (const item of list) { |
| result[keyFn(item)] = item; |
| } |
| |
| return result; |
| } |