使用ES6语法扩展Javascript中的错误&巴别塔 [英] Extending Error in Javascript with ES6 syntax & Babel

问题描述

我试图用ES6和Babel扩展Error。它没有用。

I am trying to extend Error with ES6 and Babel. It isn't working out.

class MyError extends Error {
  constructor(m) {
    super(m);
  }
}

var error = new Error("ll");
var myerror = new MyError("ll");
console.log(error.message) //shows up correctly
console.log(myerror.message) //shows empty string

Error对象永远不会得到正确的消息集。

The Error object never get the right message set.

尝试使用Babel REPL 。

现在我在SO上看到了一些解决方案（这里举例说明），但它们似乎都非ES6 -y。如何以漂亮的ES6方式做到这一点？ （这是在Babel工作）

Now I have seen a few solutions on SO (for example here), but they all seem very un-ES6-y. How to do it in a nice, ES6 way? (That is working in Babel)

推荐答案

根据KarelBílek的回答，我会对<$ c做一个小改动$ c> constructor ：

Based on Karel Bílek's answer, I'd make a small change to the constructor:

class ExtendableError extends Error {
  constructor(message) {
    super(message);
    this.name = this.constructor.name;
    if (typeof Error.captureStackTrace === 'function') {
      Error.captureStackTrace(this, this.constructor);
    } else { 
      this.stack = (new Error(message)).stack; 
    }
  }
}    

// now I can extend

class MyError extends ExtendableError {}

var myerror = new MyError("ll");
console.log(myerror.message);
console.log(myerror instanceof Error);
console.log(myerror.name);
console.log(myerror.stack);

这将在堆栈中打印 MyError ，而不是泛型错误。

This will print MyError in the stack, and not the generic Error.

它还会将错误消息添加到堆栈跟踪 - 这是从Karel的例子。

It will also add the error message to the stack trace - which was missing from Karel's example.

如果它可用，它还将使用 captureStackTrace 。

It will also use captureStackTrace if it's available.

使用Babel 6，您需要 transform-b​​uiltin-extend （ npm ）为此工作。

With Babel 6, you need transform-builtin-extend (npm) for this to work.

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