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Five ways to declare a function in JavaScript

JavaScript treats functions as first-class objects, meaning you could use functions as objects: assign them to variables, pass them to functions,return them from funvtions, assgin them to objects...

There are five ways to declare a JavaScripy function:

1. Use named function​

function greet(name){
    return 'Hello'+name
}

2. Assign function to a variable(function expression)​

const greet2= function(name){
    return 'Hello'+name
}

3. Use arrow function expression​

const greet3=(name)=>{
    return 'Hello'+name
}

4.Use shorthand arrow function​

const greet4=(name)=>'Hello'+name

JS people seem to be obessed with one line codes, and shorthand arror function is a good way to do it.

5.Use function constructer​

const greet5=new Function('name,'return "hello"+name)

This is an perfect example that function is treated as an object in JS. Though I don't remember seeing this syntax in real code.

Apparently this is also an unsafe way to declare a function in the eyes of TypeScript, so don't use it.