Javascript:变量作为数组键 [英] Javascript: variable as array key

问题描述

我正在构建和数组，其中我的数组键来自这样的变量:

I im building and array where my array key is from a variable like this:

var art = $('#article_id').val();
var stk =  $('#stk').val();
elements ={ art : stk };
alert(elements[art]);

但我最终得到这个输出 art=>50 而不是 5123=>50

but i end up with this output art=>50 instead of 5123=>50

推荐答案

ECMAScript 2015(又名 ES6 Harmony)

ES 2015 通过名为计算属性名称的功能为此提供支持(尽管相关的规范的部分被称为对象初始值设定项").

ECMAScript 2015 (aka ES6 Harmony)

ES 2015 provides support for this through a feature called computed property names (although the relevant section of the spec is called "Object Initializer").

简单地说，用方括号将变量(通常是任何表达式)括起来以对其进行评估并将结果用作属性名称.在你的例子中，这将是

Simply put, surround the variable (in general, any expression) with square brackets to evaluate it and use the result as a property name. In your example that would be

elements = { [art]: stk };

原始答案(针对 ES5)

你不能像那样创建对象字面量.你需要写

Original answer (targeting ES5)

You cannot create object literals like that. You need to write

elements = {};
elements[art] = stk;

elements = { art: stk } 之所以不起作用，是因为它等价于elements = { "art": stk }(带引号).只要 art 是合法标识符，这两个版本在 JavaScript 中是等效的，第二个版本清楚地说明了发生了什么.

The reason why elements = { art: stk } does not work is because it is equivalent to elements = { "art": stk } (with quotes). The two versions are equivalent in JavaScript as long as art is a legal identifier, and the second version makes it clear what's going on.

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