params javascript code example

Example 1: get params js

// www.example.com/users?token=12345

let params = (new URL(document.location)).searchParams;
let token = params.get("token");
// 12345

Example 2: javascript function variable arguments

function foo() {
  for (var i = 0; i < arguments.length; i++) {
    console.log(arguments[i]);
  }
}

foo(1,2,3);
//1
//2
//3

Example 3: javascript function multiple parameters

function sum(...values) {
    console.log(values);
}
sum(1);
sum(1, 2);
sum(1, 2, 3);
sum(1, 2, 3, 4);


function sum(...values) {
    let sum = 0;
    for (let i = 0; i < values.length; i++) {
        sum += values[i];
    }
  
    return sum;
}
console.log(sum(1)); //1
console.log(sum(1, 2)); //3
console.log(sum(1, 2, 3)); // 5
console.log(sum(1, 2, 3, 4)); //10

Example 4: arguments object in javascript

var sum = 0;
function addAll(){
    for (var i = 0; i<arguments.length; i++){
        sum+=arguments[i];
    }
    console.log(sum);
}

addAll(1, 2, 3, 4, 5, 6, 7, 8, 9,10); //we can provide inifite numbers as argument

Example 5: rest parameters

// Before rest parameters, "arguments" could be converted to a normal array using:

function f(a, b) {

  let normalArray = Array.prototype.slice.call(arguments)
  // -- or --
  let normalArray = [].slice.call(arguments)
  // -- or --
  let normalArray = Array.from(arguments)

  let first = normalArray.shift()  // OK, gives the first argument
  let first = arguments.shift()    // ERROR (arguments is not a normal array)
}

// Now, you can easily gain access to a normal array using a rest parameter

function f(...args) {
  let normalArray = args
  let first = normalArray.shift() // OK, gives the first argument
}

Example 6: parameters in javascript

function myFunction(x, y) {
  if (y === undefined) {
    y = 2;
  }
}