blob: 92a6dbf7741d26a1466cc4f27ffb6acae242b5d3 (
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
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
83
84
85
86
87
88
89
90
|
# p-limit [](https://travis-ci.org/sindresorhus/p-limit)
> Run multiple promise-returning & async functions with limited concurrency
## Install
```
$ npm install p-limit
```
## Usage
```js
const pLimit = require('p-limit');
const limit = pLimit(1);
const input = [
limit(() => fetchSomething('foo')),
limit(() => fetchSomething('bar')),
limit(() => doSomething())
];
(async () => {
// Only one promise is run at once
const result = await Promise.all(input);
console.log(result);
})();
```
## API
### pLimit(concurrency)
Returns a `limit` function.
#### concurrency
Type: `number`<br>
Minimum: `1`
Concurrency limit.
### limit(fn, ...args)
Returns the promise returned by calling `fn(...args)`.
#### fn
Type: `Function`
Promise-returning/async function.
#### ...args
Any arguments to pass through to `fn`.
Support for passing arguments on to the `fn` is provided in order to be able to avoid creating unnecessary closures. You probably don't need this optimization unless you're pushing a *lot* of functions.
### limit.activeCount
The number of promises that are currently running.
### limit.pendingCount
The number of promises that are waiting to run (i.e. their internal `fn` was not called yet).
## FAQ
### How is this different from the [`p-queue`](https://github.com/sindresorhus/p-queue) package?
This package is only about limiting the number of concurrent executions, while `p-queue` is a fully featured queue implementation with lots of different options, introspection, and ability to pause and clear the queue.
## Related
- [p-queue](https://github.com/sindresorhus/p-queue) - Promise queue with concurrency control
- [p-throttle](https://github.com/sindresorhus/p-throttle) - Throttle promise-returning & async functions
- [p-debounce](https://github.com/sindresorhus/p-debounce) - Debounce promise-returning & async functions
- [p-all](https://github.com/sindresorhus/p-all) - Run promise-returning & async functions concurrently with optional limited concurrency
- [More…](https://github.com/sindresorhus/promise-fun)
## License
MIT © [Sindre Sorhus](https://sindresorhus.com)
|
