1 | /**
|
2 | * @fileoverview `Map` to load rules lazily.
|
3 | * @author Toru Nagashima <https://github.com/mysticatea>
|
4 | */
|
5 | ;
|
6 |
|
7 | const debug = require("debug")("eslint:rules");
|
8 |
|
9 | /** @typedef {import("./types").Rule} Rule */
|
10 |
|
11 | /**
|
12 | * The `Map` object that loads each rule when it's accessed.
|
13 | * @example
|
14 | * const rules = new LazyLoadingRuleMap([
|
15 | * ["eqeqeq", () => require("eqeqeq")],
|
16 | * ["semi", () => require("semi")],
|
17 | * ["no-unused-vars", () => require("no-unused-vars")],
|
18 | * ])
|
19 | *
|
20 | * rules.get("semi") // call `() => require("semi")` here.
|
21 | *
|
22 | * @extends {Map<string, () => Rule>}
|
23 | */
|
24 | class LazyLoadingRuleMap extends Map {
|
25 |
|
26 | /**
|
27 | * Initialize this map.
|
28 | * @param {Array<[string, function(): Rule]>} loaders The rule loaders.
|
29 | */
|
30 | constructor(loaders) {
|
31 | let remaining = loaders.length;
|
32 |
|
33 | super(
|
34 | debug.enabled
|
35 | ? loaders.map(([ruleId, load]) => {
|
36 | let cache = null;
|
37 |
|
38 | return [
|
39 | ruleId,
|
40 | () => {
|
41 | if (!cache) {
|
42 | debug("Loading rule %o (remaining=%d)", ruleId, --remaining);
|
43 | cache = load();
|
44 | }
|
45 | return cache;
|
46 | }
|
47 | ];
|
48 | })
|
49 | : loaders
|
50 | );
|
51 |
|
52 | // `super(...iterable)` uses `this.set()`, so disable it here.
|
53 | Object.defineProperty(LazyLoadingRuleMap.prototype, "set", {
|
54 | configurable: true,
|
55 | value: void 0
|
56 | });
|
57 | }
|
58 |
|
59 | /**
|
60 | * Get a rule.
|
61 | * Each rule will be loaded on the first access.
|
62 | * @param {string} ruleId The rule ID to get.
|
63 | * @returns {Rule|undefined} The rule.
|
64 | */
|
65 | get(ruleId) {
|
66 | const load = super.get(ruleId);
|
67 |
|
68 | return load && load();
|
69 | }
|
70 |
|
71 | /**
|
72 | * Iterate rules.
|
73 | * @returns {IterableIterator<Rule>} Rules.
|
74 | */
|
75 | *values() {
|
76 | for (const load of super.values()) {
|
77 | yield load();
|
78 | }
|
79 | }
|
80 |
|
81 | /**
|
82 | * Iterate rules.
|
83 | * @returns {IterableIterator<[string, Rule]>} Rules.
|
84 | */
|
85 | *entries() {
|
86 | for (const [ruleId, load] of super.entries()) {
|
87 | yield [ruleId, load()];
|
88 | }
|
89 | }
|
90 |
|
91 | /**
|
92 | * Call a function with each rule.
|
93 | * @param {Function} callbackFn The callback function.
|
94 | * @param {any} [thisArg] The object to pass to `this` of the callback function.
|
95 | * @returns {void}
|
96 | */
|
97 | forEach(callbackFn, thisArg) {
|
98 | for (const [ruleId, load] of super.entries()) {
|
99 | callbackFn.call(thisArg, load(), ruleId, this);
|
100 | }
|
101 | }
|
102 | }
|
103 |
|
104 | // Forbid mutation.
|
105 | Object.defineProperties(LazyLoadingRuleMap.prototype, {
|
106 | clear: { configurable: true, value: void 0 },
|
107 | delete: { configurable: true, value: void 0 },
|
108 | [Symbol.iterator]: {
|
109 | configurable: true,
|
110 | writable: true,
|
111 | value: LazyLoadingRuleMap.prototype.entries
|
112 | }
|
113 | });
|
114 |
|
115 | module.exports = { LazyLoadingRuleMap };
|