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Learning TypeScript 2.x - Second Edition
book

Learning TypeScript 2.x - Second Edition

by Remo H. Jansen
April 2018
Beginner content levelBeginner
536 pages
13h 21m
English
Packt Publishing
Content preview from Learning TypeScript 2.x - Second Edition

The Error class

When a runtime error takes place, an instance of the Error class is thrown:

throw new Error(); 

We can create custom errors in a couple of different ways. The easiest way to achieve it is by passing a string as an argument to the Error class constructor:

throw new Error("My basic custom error"); 

If we need more customizable and advanced control over custom exceptions, we can use inheritance to achieve it:

export class Exception extends Error { 
 
    public constructor(public message: string) { 
        super(message); 
        // Set the prototype explicitly. 
        Object.setPrototypeOf(this, Exception.prototype); 
    } 
    public sayHello() { 
        return `hello ${this.message}`; 
    } 
} 

In the preceding code snippet, we have declared a class named Exception, which inherits ...

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Publisher Resources

ISBN: 9781788391474Supplemental Content