readme.md 2.2KB
p-throttle
Throttle promise-returning & async functions
It also works with normal functions.
Useful for rate limiting calls to an external API, for example.
Install
$ npm install p-throttle
Usage
Here, the throttled function is only called twice a second:
const pThrottle = require('p-throttle');
const now = Date.now();
const throttle = pThrottle({
limit: 2,
interval: 1000
});
const throttled = throttle(index => {
const secDiff = ((Date.now() - now) / 1000).toFixed();
return Promise.resolve(`${index}: ${secDiff}s`);
});
for (let i = 1; i <= 6; i++) {
throttled(i).then(console.log);
}
//=> 1: 0s
//=> 2: 0s
//=> 3: 1s
//=> 4: 1s
//=> 5: 2s
//=> 6: 2s
API
pThrottle(options)
Returns a throttle function.
Returns a throttled version of fn.
options
Type: object
Both the limit and interval options must be specified.
limit
Type: number
Maximum number of calls within an interval.
interval
Type: number
Timespan for limit in milliseconds.
strict
Type: boolean\
Default: false
Use a strict, more resource intensive, throttling algorithm. The default algorithm uses a windowed approach that will work correctly in most cases, limiting the total number of calls at the specified limit per interval window. The strict algorithm throttles each call individually, ensuring the limit is not exceeded for any interval.
throttle(function_)
function_
Type: Function
Promise-returning/async function or a normal function.
throttledFn.abort()
Abort pending executions. All unresolved promises are rejected with a pThrottle.AbortError error.
throttledFn.isEnabled
Type: boolean\
Default: true
Whether future function calls should be throttled and count towards throttling thresholds.
Related
- p-debounce - Debounce promise-returning & async functions
- p-limit - Run multiple promise-returning & async functions with limited concurrency
- p-memoize - Memoize promise-returning & async functions
- More…