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throttle.js
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throttle.js
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import curry from './curry';
import _enforceFunction from './internal/_enforceFunction';
import _enforceInterval from './internal/_enforceInterval';
function throttle(interval, operation) {
_enforceInterval(interval);
_enforceFunction(operation);
let lastArgs;
let lastResult;
let lastCall = 0;
let timer = null;
function cancel() {
clearTimeout(timer);
timer = null;
}
function runner() {
lastCall = Date.now();
cancel();
lastResult = operation(...lastArgs);
}
function throttled(...args) {
lastArgs = args;
if (Date.now() - lastCall >= interval) {
runner();
} else {
timer = setTimeout(runner, interval);
}
return lastResult;
}
throttled.cancel = cancel;
return throttled;
}
/**
* Ensures `operation` is only called once every `interval` milliseconds.
*
* @param {number} interval of milliseconds
* @param {Function} operation
* @return {any} the most recent result of `operation`
*/
export default curry(throttle);