How to throw an error without throw

Question

So recently I was asked a question :

Is there a way to throw an error without using throw in javaScript ?

As far as I knew about errors, there was only one way to throw an error in JavaScript and that was using throw statement in JavaScript like so :

var myFunc = () => {
  // some code here 
  throw 'Some error' // in a conditional 
  // some more code
}

try {
  myFunc()
}catch(e) {
  console.log(e)
}

And not knowing any other way I said No, there is no other way. But now I'm wondering whether I was right ?

So the question is whether or not you can throw a custom error in JavaScript without using throw

---

Restrictions :

• Kindly no using eval , Function.
• Don't use throw in your code

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Additional :

If you can throw an error without using the word Error

Answer 1

生成器确实有一个throw方法，通常用于将异常抛出到生成器函数代码中（在yield表达式的位置，类似于next），但是如果没有抓住它的气泡：

(function*(){})().throw(new Error("example"))

当然，这是一个黑客而不是好的风格，我不知道他们的期望是什么。特别是＆＃34;没有除零＆＃34;要求是粗略的，因为除以零不会在JS中抛出异常。

Answer 2

如果您只想抛出错误，那么只需执行无效操作即可。我在下面列出了几个。在浏览器控制台上运行它们以查看错误（在chrome和firefox上测试）。

var myFunc = () => {
  encodeURI('\uD800');    // URIError
  a = l;                  // ReferenceError
  null.f()                // TypeError
}


try {
  myFunc()
}catch(e) {
  console.log(e);
}

Answer 3

＆＃13;

＆＃13;

function throwErrorWithoutThrow(msg) {
  // get sample error 
  try {
    NaN();
  } catch (typeError) {
    // aquire reference to Error
    let E = typeError.__proto__.__proto__.constructor;

    // prepare custom Error
    let error = E(msg);

    // throw custom Error
    return Promise.reject(error);
  }
}

throwErrorWithoutThrow("hi")
  /* catch the error, you have to use .catch as this is a promise
  that's the only drawback, you can't use try-catch to catch these errors */
  .catch((e) => {
    console.log("Caught You!");
    console.error(e);
  });

＆＃13;

＆＃13;

＆＃13;

Answer 4

我认为，如果你想使用try...catch块，你需要抛出一些东西才能进入catch部分。你可以使用几乎所有失败的错误（如其他帖子中提到的那样）。

如果在某些时候，你想要 run-or-die 而不必亲自编写throw语句，你总是可以做一个断言：

const myFunction = () => {
  try {
    assert.fail();
    console.log(`Did not work :)`);
  } catch (e) {
    console.log(`OK`);
  }
};

当然，我宁愿尝试断言积极的东西（更多的禅宗），我需要继续。

Answer 5

const myTypeErr = () => `This is a Custom Err Message... \nand it`()

try {
  myTypeErr()
} catch(e) {} // catched

myTypeErr() // Uncaught TypeError: "This is a Custom Err Message... 
              // and it" is not a function