javascript 上的 find() 和 filter().shift() 之间的区别
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Difference between find() and filter().shift() on javascript
提问by neiker
I recently starting to drop underscore/lodash overuse on (some of) my projects and realize that there's no full support of findmethod in browsers. What's the difference between ES6 method findand using .shift() over filterresults
我最近开始在我的（一些）项目中放弃过度使用下划线/lodash，并意识到浏览器中没有完全支持find方法。ES6 方法find和使用 .shift()过滤结果有什么区别
var user = users.find(function() { ... } );
or
或者
var user = users.filter(function() { ... } ).shift();
I imagine there's obvious optimization over "find" method (stop iterating on fist match), but can I get unexpected results using second approach? Should I use the polyfillinstead? Why?
我想对“find”方法有明显的优化（停止迭代拳头匹配），但是我可以使用第二种方法得到意想不到的结果吗？我应该改用polyfill吗？为什么？
回答by Bergi
Apart from the obvious (and noticeable) overhead, yes, the results might vary. filterruns till the end of the array, and invokes its callback on every item; in contrast to findwhich stops after having found one. When the callback throws an exception on one of these additionally iterated elements, the outcome is different.
I don't see any good reason not to use find.
除了明显（和明显）的开销，是的，结果可能会有所不同。filter运行到数组末尾，并在每个项目上调用它的回调；相比之下find，找到一个后停止。当回调在这些额外迭代的元素之一上引发异常时，结果是不同的。
我看不出有什么好的理由不使用find.
回答by Juan Mendes
Use a polyfill; users.filter(function() { ... } ).shift();is throwing cycles away while triggering unnecessary garbage collection.
使用polyfill；users.filter(function() { ... } ).shift();在触发不必要的垃圾收集的同时丢弃循环。
filterscans the entire array and creates another arrayshiftnow has to change all the indexes on the temp array
filter扫描整个数组并创建另一个数组shift现在必须更改临时数组上的所有索引
A slightly less wasteful pattern would be to use users.filter(function() { ... } )[0]
一个稍微不那么浪费的模式是使用 users.filter(function() { ... } )[0]
