javascript异步循环_js数组异步循环-优快云博客

本文深入探讨了异步循环的概念及其实现方式，通过具体示例展示了如何利用回调函数来实现异步操作。同时，文章详细介绍了Seajs中轮询机制的应用场景及其实现代码，包括如何在特定条件下触发回调函数。

有些时候需要使用异步循环, 整理一下代码,如下

list 循环数组

run 循环要执行的函数

cb 循环结束调用的函数

function asynLoop(list, run, cb){

var i = 0, len = list.length;

function next(){

if (i<len) {

run(i++, list[i], next);

} else if (typeof cb==='function') {

cb();

}

next();

}

循环要执行的函数代码

i 循环数组下标

v 循环数组值

next 下一步函数

function run(i, v, next){

console.log(i);

next();

}

循环结束调用的函数代码

function cb(){

console.log('end');

}

/* 使用示例*/

var list = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15];

asynLoop(list, run, cb);

seajs 中的轮询

function poll(node, callback) {
  var isLoaded
  //do
  node++;
  if (node>100) {
    isLoaded = true
  }
  setTimeout(function() {
    if (isLoaded) {
      // Place callback in here due to giving time for style rendering.
      callback()
    } else {
      poll(node, callback)
    }
  }, 1)
}

function poll(node, callback) {
var isLoaded
//do
node++;
if (node>100) {
isLoaded = true
}
setTimeout(function() {
if (isLoaded) {
// Place callback in here due to giving time for style rendering.
callback()
} else {
poll(node, callback)
}
}, 1)
}

function poll(node, callback) {
  var isLoaded
  //do
  node++;
  if (node>100) {
    isLoaded = true
  }
  setTimeout(function() {
    if (isLoaded) {
      // Place callback in here due to giving time for style rendering.
      callback()
    } else {
      poll(node, callback)
    }
  }, 1)
}  
poll(0, function(){
  console.log('async is finish!');
})

  function poll(node, callback) {
    var isLoaded
    //do
    node++;
    if (node>100) {
      isLoaded = true
    }

    setTimeout(function() {
      if (isLoaded) {
        // Place callback in here due to giving time for style rendering.
        callback()
      } else {
        poll(node, callback)
      }
    }, 1)
  }  
poll(0, function(){
    console.log('async is finish!');
})

function poll(node, callback) {
  var isLoaded
  //do
  node++;
  if (node>100) {
    isLoaded = true
  }
  setTimeout(function() {
    if (isLoaded) {
      // Place callback in here due to giving time for style rendering.
      callback()
    } else {
      poll(node, callback)
    }
  }, 1)
}  
poll(0, function(){
  console.log('async is finish!');
})

function poll(node, callback) {
  var isLoaded
  //do
  node++;
  if (node>100) {
    isLoaded = true
  }
  setTimeout(function() {
    if (isLoaded) {
      // Place callback in here due to giving time for style rendering.
      callback()
    } else {
      poll(node, callback)
    }
  }, 1)
}