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JavaScript Academy · Lesson

Parameters, Defaults, Rest, and Returns

Work with parameters, default values, rest parameters, and clear return values in small, readable functions.

Intro

Goal: Pass values into functions safely and return results clearly.

  • Required vs default params
  • Rest params
  • Return values
Parameters, Defaults, Rest, and Returns — illustration 1

Simple parameter

A parameter lets callers pass a value into your function.

// Simple parameters
function greet(name) {
  // Make a message from the input
  const message = "Hello, " + name + "!";
  console.log(message);
}

greet("Ayla");
Parameters, Defaults, Rest, and Returns — illustration 2

All lessons in this course

  1. Declarations vs Expressions, Arrow Basics
  2. Parameters, Defaults, Rest, and Returns
  3. this Basics; call/apply/bind (intro)
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