Creating a single CommonJS module from several TypeScript classes

Question

I\'m trying to work out the best way to split my application into a few CommonJS modules that can be consumed by other applications.

I have 5 TS classes, and I\'d like t

Answer 1

As far as i know typescript doesn't support combining external modules yet. From their wiki on codeplex:

TypeScript has a one-to-one correspondence between external module source files and their emitted JS files. One effect of this is that it's not possible to use the --out compiler switch to concatenate multiple external module source files into a single JavaScript file.

However, you can do a trick by using internal modules in typescript, since the tsc compiler has the ability to compile them into a single file, and then you can just add one more file with a module.exports directive for the whole namespace to make it a CommonJS module.

Here is a step by step example. Let's say you have the following internal modules split into three files:

Validation.ts:

module Validation {
    export interface StringValidator {
        isAcceptable(s: string): boolean;
    }
}

ZipCodeValidator.ts

/// 
module Validation {
    var numberRegexp = /^[0-9]+$/;
    export class ZipCodeValidator implements StringValidator {
        isAcceptable(s: string) {
            return s.length === 5 && numberRegexp.test(s);
        }
    }
}

LettersOnlyValidator.ts

/// 
module Validation {
    var lettersRegexp = /^[A-Za-z]+$/;
    export class LettersOnlyValidator implements StringValidator {
        isAcceptable(s: string) {
            return lettersRegexp.test(s);
        }
    }
}

If you compile these with with the --out parameter in the tsc compiler you can combine them into a single file. However, that doesn't make them a CommonJS module. To export them you use a trick to add one more ts file called ValidationExport.ts containing the export directive for the namespace:

var module: any = module;
module.exports = Validation;

And then you can run the tsc command to compile everything to a single file called "validationmodule.js":

tsc --out validationmodule.js Validation.ts ZipCodeValidator.ts LettersOnlyValidator.ts ValidationExport.ts

The output is a CommonJS module you can use in Node.js:

var Validation = require("./validationmodule");

var zipCodeValidator = new Validation.ZipCodeValidator();
var lettersOnylValidator = new Validation.LettersOnlyValidator();

console.log(zipCodeValidator.isAcceptable("16211"));
console.log(lettersOnylValidator.isAcceptable("5555"));