Functions

Declaring functions

The function keyword can be omitted when assigning methods on an object.

let obj = {
  a(c, d) {},
  b(e, f) {},
}

obj.a() // call method a

Functions can be initialized with default parameters, which will be used only if an argument is not invoked through the function.

let func = (a, b = 2) => {
  return a + b
}

func(10) // returns 12
func(10, 5) // returns 15

Spread syntax can be used for function arguments.

let arr1 = [1, 2, 3]
let func = (a, b, c) => a + b + c

console.log(func(...arr1)) // 6