Chrome 开发者工具中的异常 console.log 行为 [英] Bizarre console.log behaviour in Chrome Developer Tools

问题描述

可能的重复:
Chrome 的 JavaScript 控制台是否懒得计算数组?

打开 Chrome 开发者工具并输入:

Open up Chrome Developer Tools and type in:

var a = [];console.log(a);a.push(1);console.log(a);

你会期望它输出类似

[]
[1]

而是输出

[1]
[1]

行为是相同的

var a = [];console.log(a);a[0] = 1;console.log(a);

谁能解释这种行为?

在 OS X 上运行 Chrome.在 32 位 Windows 7 上的行为相同.

Running Chrome on OS X. Same behaviour on 32bit Windows 7.

EDIT:无论语句是否在同一行，行为都是相同的.我只是在一行中提供了它们，以便于测试.

EDIT: The behaviour is the same regardless of whether the statements are on the same line or not. I have simply provided them on a single line to make it easy to test.

放置

var a = [];
console.log(a);
a.push(1);
console.log(a);

在一个文件中然后运行它会产生相同的行为.

in a file then running it yields the same behaviour.

编辑 x 2请参阅:http://jsfiddle.net/9N4A6/ 如果您不想制作文件测试.

EDIT x 2 See: http://jsfiddle.net/9N4A6/ if you don't feel like making a file to test.

推荐答案

试试这个:

var a = []; console.log(a.toString()); a.push(1); console.log(a.toString());

我敢打赌，并不是求值的顺序很奇怪，而是对象到可打印形式的转换发生在语句全部执行之后，此时 Chrome 已准备好实际转储日志.

It's not that the order of evaluation is strange, I bet, but that the conversion of the objects to printable form happens after the statements are all executed, at the point when Chrome is ready to actually dump out the log.

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