TYPESCRIPT

ts declare function type

type GreetFunction = (a: string) => void;

types function typescript

interface Safer_Easy_Fix {
    title: string;
    callback: () => void;
}
interface Alternate_Syntax_4_Safer_Easy_Fix {
    title: string;
    callback(): void;
}

typescript type of a function

onSubmit: () => void;
onSubmit: (value: string) => void;

typescript function

// Parameter type annotation
function greet(name: string): string {
 return name.toUpperCase();
}

console.log(greet("hello"));		// HELLO
console.log(greet(1));				// error, name is typed (string)

Function in Typescript

function sumNumbers(num1:number,num2:number):number{
    return num1*num2;
    }
const total = sumNumbers(2,4

typescript function type

interface getUploadHandlerParams {
  checker : Function
}

types function typescript

interface Param {
    title: string;
    callback: function;
}

types function typescript

interface Easy_Fix_Solution {
    title: string;
    callback: Function;
}

typescript function type

interface Date {
  toString(): string;
  setTime(time: number): number;
  // ...
}

typescript function

// Named function
function add(x: number, y: number): number {
  return x + y;
}

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

typescript function type

// define your parameter's type inside the parenthesis
// define your return type after the parenthesis

function sayHello(name: string): string  {
  console.log(`Hello, ${name}`!);
}

sayHello('Bob'); // Hello, Bob!

types function typescript

interface Alternate_Syntax_4_Advanced {
    title: string;
    callback<T extends unknown[], R = unknown>(...args?: T): R;
}

types function typescript

interface Better_still_safe_but_way_more_flexible_fix {
    title: string;
    callback: <T = unknown, R = unknown>(args?: T) => R;
}
interface Alternate_Syntax_4_Better_still_safe_but_way_more_flexible_fix {
    title: string;
    callback<T = unknown, R = unknown>(args?: T): R;
}

declare type function typescript

function printToConsole(s: string) {
  console.log(s);
}
 

typescript function

export const multiply_by7 =  (x:number):number =>{return x*7}