我想在while循环中添加一个delay/sleep:
我是这样试的:
alert('hi');
for(var start = 1; start < 10; start++) {
setTimeout(function () {
alert('hello');
}, 3000);
}
只有第一种情况是正确的:在显示alert('hi')后，它将等待3秒，然后alert('hello')将显示，但随后alert('hello')将不断重复。
我想要的是，在警报('hello')显示3秒后警报('hi')，然后它需要等待3秒的第二次警报('hello')，以此类推。
当前回答
在ES6中，你可以这样做:
对于(设I = 0;I <= 10;我+ +){ setTimeout(函数(){ console.log(我); },我* 3000) }
在ES5中，你可以这样做:
For (var I = 0;I <= 10;我+ +){ (函数(i) { setTimeout(函数(){ console.log(我); },我* 3000) }) (); ｝
原因是，let允许您声明限制在块语句或使用它的表达式范围内的变量，而不像var关键字那样全局定义变量，或局部定义整个函数，而不考虑块范围。
其他回答
我用蓝鸟的承诺。延时和递归。
函数 myLoop（i） { 返回承诺延迟（1000） .then（function（） { 如果 （i > 0） { 警报（“你好”）; 返回 myLoop（i -= 1）; } }); } 我的循环（3）; <script src=“//cdnjs.cloudflare.com/ajax/libs/bluebird/2.9.4/bluebird.min.js”></script>
const autoPlayer = (arr = [1, 2, 3, 4, 5]) => {
// Base case:
if (arr.length < 1) return
// Remove the first element from the array.
const item = arr.shift()
// Set timout
setTimeout(() => {
console.log('Hello, world!', item) // Visualisation.
autoPlayer() // Call function again.
}, 1000) // Iterate every second.
}
Hey, I know this post is very old, but this code "loops" and adds a delay to it using a recursive method. I don't think you can 'actually' delay a loop itself from iterating based on reading various comments from other people. Maybe this can help someone out! Basically the function accepts an array (in this example). On each iteration the setTimeout Javascript method is called. The function calls itself again indefinitely when the timer of the setTimeout function expires, but on each call the array becomes smaller until it reaches the base-case. I hope this can help anyone else out.
我只是想在这里发表我的意见。此函数运行具有延迟的迭代循环。请看这个jsfiddle。函数如下:
function timeout(range, time, callback){
var i = range[0];
callback(i);
Loop();
function Loop(){
setTimeout(function(){
i++;
if (i<range[1]){
callback(i);
Loop();
}
}, time*1000)
}
}
例如:
//This function prints the loop number every second
timeout([0, 5], 1, function(i){
console.log(i);
});
相当于:
//This function prints the loop number instantly
for (var i = 0; i<5; i++){
console.log(i);
}
下面是我用来循环数组的函数:
function loopOnArrayWithDelay(theArray, delayAmount, i, theFunction, onComplete){
if (i < theArray.length && typeof delayAmount == 'number'){
console.log("i "+i);
theFunction(theArray[i], i);
setTimeout(function(){
loopOnArrayWithDelay(theArray, delayAmount, (i+1), theFunction, onComplete)}, delayAmount);
}else{
onComplete(i);
}
}
你可以这样使用它:
loopOnArrayWithDelay(YourArray, 1000, 0, function(e, i){
//Do something with item
}, function(i){
//Do something once loop has completed
}
这是可行的
for (var i = 0; i < 10; i++) {
(function(i) {
setTimeout(function() { console.log(i); }, 100 * i);
})(i);
}
试试这把小提琴:https://jsfiddle.net/wgdx8zqq/
