javascript - Webpack 插件开发 - 函数调用父函数的参数

Question

在 Webpack 的文档中列出了此代码片段。我想知道callback()函数实际上是做什么的。

function MyPlugin() {
  this.startTime = Date.now();
  this.prevTimestamps = {};
}

MyPlugin.prototype.apply = function(compiler) {
  compiler.plugin('emit', function(compilation, callback) {

    var changedFiles = Object.keys(compilation.fileTimestamps).filter(function(watchfile) {
      return (this.prevTimestamps[watchfile] || this.startTime) < (compilation.fileTimestamps[watchfile] || Infinity);
    }.bind(this));

    this.prevTimestamps = compilation.fileTimestamps;
    callback();
  }.bind(this));
};

module.exports = MyPlugin;

Answer 1

这来自 Webpack@v2，但我相信它的解释和应用类似:

https://webpack.js.org/pluginsapi/compiler/

The Compiler exposes a run method which kickstarts all compilation work for webpack. When that is done, it should call the passed in callback function. All the tail end work of logging stats and errors are done in this callback function.