Can typescript export a function?

Question

Is it possible to export a simple function from a typescript module?

This isn't compiling for me.

module SayHi {     export function() {     console.log("Hi");   } } new SayHi(); 

This workitem seems to imply that you cannot but doesn't flat out say it. Is it not possible?

Answer 1

It's hard to tell what you're going for in that example. exports = is about exporting from external modules, but the code sample you linked is an internal module.

Rule of thumb: If you write module foo { ... }, you're writing an internal module; if you write export something something at top-level in a file, you're writing an external module. It's somewhat rare that you'd actually write export module foo at top-level (since then you'd be double-nesting the name), and it's even rarer that you'd write module foo in a file that had a top-level export (since foo would not be externally visible).

The following things make sense (each scenario delineated by a horizontal rule):

---

// An internal module named SayHi with an exported function 'foo' module SayHi {     export function foo() {        console.log("Hi");     }      export class bar { } }  // N.B. this line could be in another file that has a // <reference> tag to the file that has 'module SayHi' in it SayHi.foo(); var b = new SayHi.bar(); 

---

file1.ts

// This *file* is an external module because it has a top-level 'export' export function foo() {     console.log('hi'); }  export class bar { } 

file2.ts

// This file is also an external module because it has an 'import' declaration import f1 = module('file1'); f1.foo(); var b = new f1.bar(); 

---

file1.ts

// This will only work in 0.9.0+. This file is an external // module because it has a top-level 'export' function f() { } function g() { } export = { alpha: f, beta: g }; 

file2.ts

// This file is also an external module because it has an 'import' declaration import f1 = require('file1'); f1.alpha(); // invokes f f1.beta(); // invokes g 

Answer 2

To answer the title of your question directly because this comes up in Google first:

YES, TypeScript can export a function!

Here is a direct quote from the TS Documentation:

"Any declaration (such as a variable, function, class, type alias, or interface) can be exported by adding the export keyword."

Reference Link