Summary - Variables

Combine let, const, destructuring and spread to write a profile program.

Summary - Variables

In this group you saw the modern way to declare variables: let for mutable, const for fixed, var for old style. Thanks to type inference you do not write the type explicitly; with destructuring and spread/rest you easily extract and merge values.

Now there are two small tasks: one for price calculation, one for extracting values with destructuring. First recall what you learned, then apply it.

Exercise Calculate with const

Declare const price = 100 and const tax = 18. Compute total as price + tax. Call console.log(total).

Show example solution

const price = 100;
const tax = 18;
const total = price + tax;
console.log(total);

Exercise Extract values with destructuring

Define an object named point: x is 5, y is 10. Use destructuring to extract x and y. Then call console.log(x + y) to print their sum.

Show example solution

const point = { x: 5, y: 10 };
const { x, y } = point;
console.log(x + y);

Test yourself

Match the concepts

let

Mutable variable
const

Fixed variable
...

Spread/rest operator
{ a, b }

Destructuring

Destructuring reminder

const point = { x: 5, y: 10 };
const ____ = point;

Show answer

const point = { x: 5, y: 10 };
const { x, y } = point;

Next lesson: Primitive types

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