检查每一个元素 Testing Every Element

## 问题 Problem 你想针对某一个特别的条件对数组中的每一个元素进行检查。 You want to be able to check that every element in an array meets a particular condition. ## 方法 Solution 使用Array.every （ECMAScript 5）： Use Array.every (ECMAScript 5): ~~~ evens = (x for x in [1..10] by 2) evens.every (x)-> x % 2 == 0 # => true ~~~ Mozilla的JavaScript 1.6中加入了Array.every，并在ECMAScript 5 中标准化。如果想支持没有实现EC5哦浏览器，就看看[underscore.js中的`_.all`](http://documentcloud.github.com/underscore/)。 Array.every was addded to Mozilla’s Javascript 1.6 and made standard with EcmaScript 5\. If you to support browsers that do not implement EC5 then check out [`_.all` from underscore.js](http://documentcloud.github.com/underscore/). 举个真实世界中的例子，假设一个多选的下拉列表，像下面这样： For a real world example, prentend you have a multiple select list that looks like: ~~~ <select multiple id="my-select-list"> <option>1</option> <option>2</option> <option>Red Car</option> <option>Blue Car</option> </select> ~~~ 现在你想确定用户只选中的数组，让我们用Array.every看看： Now you want to verify that the user selected only numbers. Let’s use Array.every: ~~~ validateNumeric = (item)-> parseFloat(item) == parseInt(item) && !isNaN(item) values = $("#my-select-list").val() values.every validateNumeric ~~~ ## 讨论 Discussion 这个方法与Ruby中数组的all?方法类似。 This is similar to using ruby’s Array#all? method.