使用带有一个附加参数的函数的 map() 的 JS 回调 [英] JS callback using map() with a function that has one additional parameter

问题描述

我正在尝试找到一种方法，将 JS 的 Array.prototype.map() 功能与具有一个额外参数的函数一起使用(如果可能的话，我想避免必须重写内置的Array.prototype.map()).这个文档很好，但没有涵盖一个或多个附加参数"的情况:

I'm trying to find a way to use JS's Array.prototype.map() functionality with a function that has one additional parameter more (if possible at all, and I'd like to avoid having to rewrite built-in Array.prototype.map()). This documentation is very good, but does not cover the "one-or-more-additional-parameter" case:

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/地图

function doOpSingle(elem)
{
 // do something with one array element
}

var A = ["one", "two", "three", "four"];
var x = A.map(doOpSingle); // this will execute doOpSingle() on each array element

到目前为止，一切都很好.但是如果有问题的函数有两个参数，比如 e.G.您可能想要对其进行 OR 的标志(想想位掩码)

So far, so good. But what if the function in question has two parameters, like e. g. a flag you might want to OR to it (think of bit masks)

function doOpSingle2(arrelem,flag)
{
 // do something with one array element
}

var A = ["one", "two", "three", "four"];
var theFlag = util.getMask(); // call external function
var y = A.map(doOpSingle2(theFlag)); // this does not work!

当然，任何解决方案都应该不用 for 循环，因为这就是我们有map() 的原因，以使我们的代码更清晰/摆脱这些！

Any solutions should do without for loops, of course, because that's why we have map(), to make our code cleaner w/getting rid of these!

推荐答案

使用匿名函数:

A.map(function(a) {return doOpSingle2(a,theFlag);});

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