How to create an extension method in TypeScript for 'Date' data type

Question

I have tried to create an extension method in TypeScript based on this discussion (https://github.com/Microsoft/TypeScript/issues/9), but I couldn't create a working one.

Here is my code,

namespace Mynamespace {     interface Date {         ConvertToDateFromTS(msg: string): Date;     }      Date.ConvertToDateFromTS(msg: string): Date {         //conversion code here     }      export class MyClass {} } 

but its not working.

Answer 1

You need to change the prototype:

interface Date {     ConvertToDateFromTS(msg: string): Date; }  Date.prototype.ConvertToDateFromTS = function(msg: string): Date {     // implement logic }  let oldDate = new Date(); let newDate = oldDate.ConvertToDateFromTS(TS_VALUE); 

Though it looks like you want to have a static factory method on the Date object, in which case you better do something like:

interface DateConstructor {     ConvertToDateFromTS(msg: string): Date; }  Date.ConvertToDateFromTS = function(msg: string): Date {     // implement logic }  let newDate = Date.ConvertToDateFromTS(TS_VALUE);