uglify-js可以删除console.log语句吗？ [英] Can uglify-js remove the console.log statements?

问题描述

我正在使用 uglify-js 来缩小源代码。我想删除原始源代码的console.log语句。可能吗？或者有没有其他压缩工具支持这个？

I'm using uglify-js to minify the source code. I want to remove the console.log statements of the original source code. Is it possible? Or is there any other compressor tool supports this?

我在Node.js中使用如下代码。

I use the code as below in Node.js.

var uglify = require('uglify-js');
var originalSourceCode = 'var name = function(){var str = "test"; return str}; console.log("log data");';
var minifiedCode = uglify.minify(originalSourceCode, {
                fromString : true,
                mangle: {},
                warnings: true
            });
console.log(minifiedCode);

输出为：

$node m.js
{ code: 'var name=function(){var a="test";return a};console.log("log data");',
  map: 'null' }

在缩小的代码中，console.log不是删除。

In the minified code the console.log isn't removed.

推荐答案

在最新的uglify-js（v2.4.3）中，添加了一个新的压缩选项'pure_funcs'。如果我将console.log函数添加到此数组，它将在缩小的js文件中删除。下面的测试代码显示了此选项的工作原理。这正是我想要的。

In the lastest uglify-js ( v2.4.3), a new compress option ‘pure_funcs’ is added. If I add the console.log functions to this array, it will be removed in the minified js file. The test code below shows how this option works. This is exactly what I want.

// file: m.js
var uglify = require('uglify-js');
var originalSourceCode = 'var name = function(){var str = "test"; return str}; console.log("log data" + name());';
var minifiedCode = uglify.minify(originalSourceCode, {
                fromString : true,
                mangle: {},
                warnings: true,
                compress:{
                    pure_funcs: [ 'console.log' ]
                }
            });
console.log(minifiedCode);

$node m.js
WARN: Dropping side-effect-free statement [?:1,53]
{ code: 'var name=function(){var n="test";return n};',
  map: 'null' }

来自 https://github.com/mishoo/UglifyJS2 的报价

pure_funcs - 默认为null。您可以传递一组名称，UglifyJS将假定这些函数不会产生副作用。
危险：不会检查名称是否在范围内重新定义。这里有一个示例
的例子，例如var q = Math.floor（a / b）。如果变量q不是其他地方使用的
，则UglifyJS会丢弃它，但仍会保留
Math.floor（a / b），而不知道它的作用。你可以传递pure_funcs：[
'Math.floor']让它知道这个函数不会产生任何
的副作用，在这种情况下整个语句都会被丢弃。
当前实现增加了一些开销（压缩将慢了
）。

pure_funcs -- default null. You can pass an array of names and UglifyJS will assume that those functions do not produce side effects. DANGER: will not check if the name is redefined in scope. An example case here, for instance var q = Math.floor(a/b). If variable q is not used elsewhere, UglifyJS will drop it, but will still keep the Math.floor(a/b), not knowing what it does. You can pass pure_funcs: [ 'Math.floor' ] to let it know that this function won't produce any side effect, in which case the whole statement would get discarded. The current implementation adds some overhead (compression will be slower).

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