let and const

const name = "Ada"; creates a variable that cannot be reassigned; let count = 0; creates one that can. Use const by default and let only when the value has to change, which makes code easier to follow. You will see var in old code; it behaves oddly around scope and is best avoided.

Values have types: strings for text, numbers (one type for both 3 and 3.5), booleans true and false, and undefined for a variable that was declared but never given a value. typeof x tells you which. Names are case-sensitive and written in camelCase by convention: totalPrice.

const city = "Lisbon";
let visits = 0;
visits = visits + 1;
console.log(city, visits, typeof visits);   // Lisbon 1 number

Your task

Declare name with const holding any text, age with let holding a whole number, and height holding a number with a decimal point. Then add one to age (reassign it), and print the line <name> is <age>, for example Ada is 37.

One more, for later: TAX_RATE declared with const and holding 0.08. This course ends in a checkout project, and a few lessons along the way build its parts; this constant is the first, the sales tax rate the receipt uses.

Part of the final project. TAX_RATE is the sales tax rate the receipt applies. It is saved in this browser and loaded into Project: checkout when you get there.

const name = "Ada";
let age = 36;
const height = 1.7;
const TAX_RATE = 0.08;
age = age + 1;
console.log(name, "is", age);