自定义异常的Javascript:toString函数不显示预期输出

Question

本页概述了如何在Javascript中创建自定义异常：https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/throw.

但是，自定义异常没有打印预期的输出。所需输出仅在调用console.log(e.toString())时发生，但目标是使用console.log(e)查看所需输出。

console.log(e):的期望输出

500: Unexpected error

console.log(e):的实际输出

{
statusCode: 500,
statusMessage: "Unexpected error",
toString: function () {
return this.statusCode + ': ' + this.statusMessage;
}
}

代码

function TestException(statusCode, statusMessage) {
this.statusCode = statusCode;
this.statusMessage = statusMessage;
this.toString = function() {
return this.statusCode + ': ' + this.statusMessage;
};
}
try {
throw new TestException(500, 'Unexpected error');
} catch (e) {
console.log(e);
}

Answer 1

您必须有一个异常来帮助您：

const TestException = (statusCode, statusMessage) => {
this.statusCode = statusCode;
this.statusMessage = statusMessage;
this.toString = () => {
return this.statusCode + ': ' + this.statusMessage;
}
if(!isNaN(this.statusCode) || this.statusMessage !== null) {
throw this.toString();
}
}
try {
throw TestException("500", 'Unexpected error');
} catch (e) {
console.log(e);
}