Type literal in Typescript

Type literal is a type that represents a single value and nothing else. By using a value as a type, we essentially limit the possible values.

let a = true; // boolean
var b = false; // boolean
const c = true; // true
let d: true = true; // true
let e: true = false; // Error TS2322: Type 'false' is not assignalbe to type 'true'
let f: 26.218 = 26.218; // 26.218
let g: 26.218 = 10; // Error TS2322: Type '10' is not assignalbe to type '26.218'

1. a, b is mutable and Typescript inferred a boolean type.
2. c is constant, Typescript inferred a type literal true.
3. we annotate d , e , f, g as type literals, so that only specific value is assignable to it.