TypeScript's primitive types describe basic values: string, number, boolean, null and undefined, plus arrays and tuples. They are checked at compile time and then erased: the code that runs remains JavaScript. They are used to catch misuse of a value early.
Example
let age: number = 30;
let noms: string[] = ['Ada', 'Linus'];
let couple: [string, number] = ['Ada', 36];