JavaScript:在 'break' 循环内模拟 'foreach'

Question

当您迭代用户/引擎定义的函数时，实现 for 循环“中断”功能模拟的最佳方法是什么？

foreach([0,1,2,3,4],function(n){
    console.log(n);
    if (n==2)
        break;});

我曾想过以一种当函数返回“false”时会中断的方式实现 foreach - 但我想听听关于通常如何完成的想法。

Answer 1

returning false 是最常见的方法。这就是 jQuery 的迭代器函数 .each()是:

We can break the $.each() loop at a particular iteration by making the callback function return false. Returning non-false is the same as a continue statement in a for loop; it will skip immediately to the next iteration.

及其非常简化的实现:

each: function( object, callback ) {
  var i = 0, length = object.length,
  for ( var value = object[0]; 
        i < length && callback.call( value, i, value ) !== false; // break if false is returned by the callback 
        value = object[++i] ) {}
  return object;
}