Type-checking vanilla JS with JSdoc and the TS typechecker

freeze-object.js

// @ts-check

/**
 * @typedef {string | number | boolean | null | undefined} Primitive
 */

/**
 * @template { Primitive } T
 * @template {T | Record.<string,T>} R
 * @param {R} v 
 * @returns {R}
 */
const freeze = (v) => (v)

const person = freeze({
    name: 'Ayo',
    age: 14
});

person.name = 'Anything else' // ERROR: Type '"Anything else"' is not assignable to type '"Ayo"'.
person.age = 15 // ERROR: Type '15' is not assignable to type '14'.

type-checking.js

// @ts-check

let nickName = 'Ramon'; // here type is inferred as string
nickName = 1; // ERROR: Type 'number' is not assignable to type 'string'.

/** @type{string} */ // explicit type setting
let title;
title = 1; // ERROR: Type 'number' is not assignable to type 'string'.

This solution will need your (and your teammate's) IDE's TypeScript typechecker to understand JSdoc. Fortunately, popular IDEs and code editors like VS Code can do this out of the box if you're already coding TypeScript.