Joe Wood Notes

---

Variables

let x: number = 100;

---

Constants

const PI: number = 3.1415; // Immutable constant

---

Literals

The following primitive literals are covered by Typescript:

let myInt: number = 10;
let myBinary: number = 0b1010;
let myOctal: number = 0o12;
let myHex: number = 0xa;
let myFloat: number = 10.5;
let mySciNot: number = 2.0e3;
let myBool: boolean = true;
let myNull: null = null;
let myUndefined: undefined = undefined;

String literals:

let myStr: string = "hello";
let myStrDouble: string = "hello";
let myMultiLine: string = `hello
there`; // Template literals allow multi-line strings

let myRaw: string = String.raw`New\nLine`; // Ignores escape sequences
let myFormatted: string = `Hello ${name}`; // String interpolation

Complex literals

let myArray: number[] = [1, 2, 3]; // Standard array
let myTuple: [number, number, number] = [1, 2, 3]; // Fixed-size tuple
let mySingleTuple: [number] = [42]; // Tuple with one element

let myObject: { key: string; age: number } = { key: "value", age: 30 }; // Object type
let mySet: Set<number> = new Set([1, 2, 3]); // Set type
let myEmptySet: Set<number> = new Set(); // Empty set

let myBuffer: ArrayBuffer = new ArrayBuffer(8); // Equivalent to `bytes`
let myTypedArray: Uint8Array = new Uint8Array([104, 101, 108, 108, 111]); // Equivalent to `bytearray`