A Typed array of functions

Question

I'm struggling to figure out if it's possible in TypeScript to declare a statically typed array of functions.

For example, I can do this:

foo: (data:string) => void = function (data) {}; 

But if I want foo to be an array of functions that take a string and return nothing, how do I do that?

foo: (data:string) => void [] = []; 

Doesn't work because TypeScript thinks it's a function that takes a string and returns an array of void, and it doesn't seem to like me trying to wrap the function in brackets.

Any ideas?

Answer: Thanks to mohamed below, here's an example that works in the TypeScript Playground:

class whatever { public foo: { (data: string): void; }[] = [];      dofoo() {         for (var i=0; i < this.foo.length; i++) {              this.foo[i]("test");         }     } }  var d = new whatever();  d.foo.push(function(bar){alert(bar)}) d.foo.push(function(bar){alert(bar.length.toString())})  d.dofoo(); 

Answer 1

You can find this in the language spec section 3.6.4:

foo: { (data: string): void; } [] 

Answer 2

Other (newer, more readable) ways to type an array of functions using fat arrows:

let foo: Array<(data: string) => void>; let bar: ((data: string) => void)[];