Summary

  • let is a modern variable declaration.

  • Use let over old-school var to declare variables because var has no block scope and can only be either function-scoped or global-scoped.

  • The variable name must contain only letters, digits, or the symbols $ and _, and the first character must not be a digit.

  • In JavaScript, camelCase is commonly used for multiple words name.

  • Use const instead of let to declare a constant variable that cannot be changed after assignment. Constants known prior to execution are usually named using capital letters and underscores, and constants that are calculated in run-time are named using camelCase.

Tasks

  • Working with variables

    let admin, name
name = "John"
admin = name
alert(admin)

  • Giving the right name

    let ourPlanetName = "Earth"
let currentUserName

  • Uppercase const?

    const BIRTHDAY = '18.04.1982'
const age = someCode(BIRTHDAY)

References