til/javascript/accessing-arguments-to-a-function.md

Accessing Arguments To A Function

The arguments object is available within any JavaScript function. It is an array-like object with all of the arguments to the function. Even if not all of the arguments are referenced in the function signature, they can still be accessed via the arguments object.

For ES6+ compatibility, the spread operator used via rest parameters is preferred over the arugments object when accessing an abritrary number of function arguments.

function argTest(one) {
  console.log(one);
  console.log(arguments);
  console.log(arguments[1]);
}

argTest(1);
// 1
// [1]
// undefined

argTest(1, 'two', true);
// 1
// [1,'two',true]
// 'two'

See the Arguments object docs on MDN for more details.

h/t Dorian Karter