1
|
declare namespace mem {
|
2
|
interface CacheStorage<KeyType extends unknown, ValueType extends unknown> {
|
3
|
has(key: KeyType): boolean;
|
4
|
get(key: KeyType): ValueType | undefined;
|
5
|
set(key: KeyType, value: ValueType): void;
|
6
|
delete(key: KeyType): void;
|
7
|
clear?: () => void;
|
8
|
}
|
9
|
|
10
|
interface Options<
|
11
|
ArgumentsType extends unknown[],
|
12
|
CacheKeyType extends unknown,
|
13
|
ReturnType extends unknown
|
14
|
> {
|
15
|
/**
|
16
|
Milliseconds until the cache expires.
|
17
|
|
18
|
@default Infinity
|
19
|
*/
|
20
|
readonly maxAge?: number;
|
21
|
|
22
|
/**
|
23
|
Determines the cache key for storing the result based on the function arguments. By default, if there's only one argument and it's a [primitive](https://developer.mozilla.org/en-US/docs/Glossary/Primitive), it's used directly as a key, otherwise it's all the function arguments JSON stringified as an array.
|
24
|
|
25
|
You could for example change it to only cache on the first argument `x => JSON.stringify(x)`.
|
26
|
*/
|
27
|
readonly cacheKey?: (...arguments: ArgumentsType) => CacheKeyType;
|
28
|
|
29
|
/**
|
30
|
Use a different cache storage. You could for example use a `WeakMap` instead or [`quick-lru`](https://github.com/sindresorhus/quick-lru) for a LRU cache.
|
31
|
|
32
|
@default new Map()
|
33
|
*/
|
34
|
readonly cache?: CacheStorage<CacheKeyType, {data: ReturnType; maxAge: number}>;
|
35
|
|
36
|
/**
|
37
|
Cache rejected promises.
|
38
|
|
39
|
@default false
|
40
|
*/
|
41
|
readonly cachePromiseRejection?: boolean;
|
42
|
}
|
43
|
}
|
44
|
|
45
|
declare const mem: {
|
46
|
/**
|
47
|
[Memoize](https://en.wikipedia.org/wiki/Memoization) functions - An optimization used to speed up consecutive function calls by caching the result of calls with identical input.
|
48
|
|
49
|
@param fn - Function to be memoized.
|
50
|
|
51
|
@example
|
52
|
```
|
53
|
import mem = require('mem');
|
54
|
|
55
|
let i = 0;
|
56
|
const counter = () => ++i;
|
57
|
const memoized = mem(counter);
|
58
|
|
59
|
memoized('foo');
|
60
|
//=> 1
|
61
|
|
62
|
// Cached as it's the same arguments
|
63
|
memoized('foo');
|
64
|
//=> 1
|
65
|
|
66
|
// Not cached anymore as the arguments changed
|
67
|
memoized('bar');
|
68
|
//=> 2
|
69
|
|
70
|
memoized('bar');
|
71
|
//=> 2
|
72
|
```
|
73
|
*/
|
74
|
<
|
75
|
ArgumentsType extends unknown[],
|
76
|
ReturnType extends unknown,
|
77
|
CacheKeyType extends unknown
|
78
|
>(
|
79
|
fn: (...arguments: ArgumentsType) => ReturnType,
|
80
|
options?: mem.Options<ArgumentsType, CacheKeyType, ReturnType>
|
81
|
): (...arguments: ArgumentsType) => ReturnType;
|
82
|
|
83
|
/**
|
84
|
Clear all cached data of a memoized function.
|
85
|
|
86
|
@param fn - Memoized function.
|
87
|
*/
|
88
|
clear<ArgumentsType extends unknown[], ReturnType extends unknown>(
|
89
|
fn: (...arguments: ArgumentsType) => ReturnType
|
90
|
): void;
|
91
|
|
92
|
// TODO: Remove this for the next major release
|
93
|
default: typeof mem;
|
94
|
};
|
95
|
|
96
|
export = mem;
|