节流和防抖

[sakila1012]

// 节流throttle，多次触发但只执行一部分，（恒时间间距执行）
function throttle(method, threshold, ctx) {
let timer = null;
return function () {
const args = [].slice.call(arguments);
if (!timer) {
timer = setTimeout(function () {
timer = null;
method.apply(ctx, args);
}, threshold);
}
}
}

// 防抖debounce, 多次触发但只执行一次，（时间差大于阈值才执行）
function debounce(method, threshold, ctx) {
let timer = null;
return function () {
const args = [].slice.call(arguments);
timer && clearTimeout(timer);
timer = setTimeout(function () {
method.apply(ctx, args);
}, threshold);
};
}

// 轮循函数
// usage: wait(fn.bind(ctx, ...args), 10000);
function wait(fn, timeout, tick) {
timeout = timeout || 5000;
tick = tick || 250;
var timeoutTimer = null;
var execTimer = null;

return new Promise(function (resolve, reject) {

	timeoutTimer = setTimeout(function () {
		clearTimeout(execTimer);
		reject(new Error('polling fail because timeout'));
	}, timeout);

	tickHandler(fn);

	function tickHandler(fn) {
		var ret = fn();
		if (!ret) {
			execTimer = setTimeout(function () {
				tickHandler(fn);
			}, tick)
		} else {
			clearTimeout(timeoutTimer);
			resolve();
		}
	}
});

}

var n = 1;
wait(function () {
console.log(n++);
return n > 10;
}, 2000, 300).then(function () {
console.log('===== end ====')
}).catch(function (err) {
console.error('error', err);
});