/
index.js
82 lines (62 loc) · 1.6 KB
/
index.js
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
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
'use strict';
const mimicFn = require('mimic-fn');
const isPromise = require('p-is-promise');
const mapAgeCleaner = require('map-age-cleaner');
const cacheStore = new WeakMap();
const defaultCacheKey = (...args) => {
if (args.length === 0) {
return '__defaultKey';
}
if (args.length === 1) {
const [firstArgument] = args;
if (
firstArgument === null ||
firstArgument === undefined ||
(typeof firstArgument !== 'function' && typeof firstArgument !== 'object')
) {
return firstArgument;
}
}
return JSON.stringify(args);
};
module.exports = (fn, options) => {
options = Object.assign({
cacheKey: defaultCacheKey,
cache: new Map(),
cachePromiseRejection: false
}, options);
if (typeof options.maxAge === 'number') {
mapAgeCleaner(options.cache);
}
const {cache} = options;
options.maxAge = options.maxAge || 0;
const setData = (key, data) => {
cache.set(key, {
data,
maxAge: Date.now() + options.maxAge
});
};
const memoized = function (...args) {
const key = options.cacheKey(...args);
if (cache.has(key)) {
const c = cache.get(key);
return c.data;
}
const ret = fn.call(this, ...args);
setData(key, ret);
if (isPromise(ret) && options.cachePromiseRejection === false) {
// Remove rejected promises from cache unless `cachePromiseRejection` is set to `true`
ret.catch(() => cache.delete(key));
}
return ret;
};
mimicFn(memoized, fn);
cacheStore.set(memoized, options.cache);
return memoized;
};
module.exports.clear = fn => {
const cache = cacheStore.get(fn);
if (cache && typeof cache.clear === 'function') {
cache.clear();
}
};