Flash cards
Review the key moves
What is the main idea behind TypeScript Simple Types?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
Which statement best captures the main point of this lesson?
Complete the missing token from the example code.
___ isActive: boolean = true;Put the learning moves in the order that makes the concept easiest to apply.
TypeScript enhances JavaScript by adding static types.
JavaScript and TypeScript Primitives
The most basic types in TypeScript are called primitives .
These types form the building blocks of more complex types in your applications.
TypeScript includes all JavaScript primitives plus additional type features.
Here are the five primitive types you'll use most often:
Boolean
Represents true/false values.
Used for flags, toggles, and conditions.
Example
let isActive: boolean = true;
let hasPermission = false; // TypeScript infers 'boolean' typeNumber
Represents both integers and floating-point numbers.
TypeScript uses the same number type for all numeric values.
Example
let decimal: number = 6;
let hex: number = 0xf00d; // Hexadecimal
let binary: number = 0b1010; // Binary
let octal: number = 0o744; // Octal
let float: number = 3.14; // Floating pointString
Represents text data.
Can use single quotes ('), double quotes ("), or backticks (`) for template literals.
Example
let color: string = "blue";
let fullName: string = 'John Doe';
let age: number = 30;
let sentence: string = `Hello, my name is ${fullName} and I'll be ${age + 1} next year.`;BigInt (ES2020+)
Represents whole numbers larger than 2 53 - 1.
Example
const hugeNumber = BigInt(9007199254740991);Symbol
Creates unique identifiers.
Useful for creating unique property keys and constants.
Example
const uniqueKey: symbol = Symbol('description');
const obj = {
[uniqueKey]: 'This is a unique property'
};
console.log(obj[uniqueKey]); // "This is a unique property"