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TypeScript function types

Function types in TypeScript 

TypeScript function types make it possible for programmers to express the expected signature of a function. A function signature is a sequence of parameter types plus a return type.

 

TypeScript function type sample code:

 

function MyVote(candidate: string, callback: (result: string) => any) { //here some code ... }
 
    MyVote("MyParty", function (result: string) { if (result === "MyParty") { //here ur code ... } } );

In detail:

A function’s type has the same two parts: the type of the arguments and the return type. When writing out the whole function type, both parts are required. We write out the parameter types just like a parameter list, giving each parameter a name and a type.

//simple js function

        function add(x, y) {
            return x + y;
        }

 

 //typescript simple function type implementation

        function add(x: number, y: number): number {
            return x + y;
        }
        let myAdd = function (x: number, y: number): number { return x + y; };

 

 

//Typescript proper function type use

      let myAdd: (baseValue: number, increment:
number) => number =
      function (x: number, y: number): number { return x + y; };