blob: de982cc3ffab13a276b464b1bf73f02d48e21fc6 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
|
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
// @ts-check
"use strict";
/**
* TypeScript can't understand the lazyRequireGetter mechanism, due to how it defines
* properties as a getter. This function, instead provides lazy loading in a
* TypeScript-friendly manner. It applies the lazy load memoization to each property
* of the provided object.
*
* Example usage:
*
* const lazy = createLazyLoaders({
* moduleA: () => require("module/a"),
* moduleB: () => require("module/b"),
* });
*
* Later:
*
* const moduleA = lazy.moduleA();
* const { objectInModuleB } = lazy.moduleB();
*
* @template {{ [key: string]: () => any }} T
* @param {T} definition - An object where each property has a function that loads a module.
* @returns {T} - The load memoized version of T.
*/
function createLazyLoaders(definition) {
/** @type {any} */
const result = {};
for (const [key, callback] of Object.entries(definition)) {
/** @type {any} */
let cache;
result[key] = () => {
if (cache === undefined) {
cache = callback();
}
return cache;
};
}
return result;
}
// Provide an exports object for the JSM to be properly read by TypeScript.
/** @type {any} */
var module = {};
module.exports = {
createLazyLoaders,
};
// Object.keys() confuses the linting which expects a static array expression.
// eslint-disable-next-line
var EXPORTED_SYMBOLS = Object.keys(module.exports);
|
