In TypeScript, u can easily declare constants using as const:

const Meal = {
  Breakfast: 'breakfast',
  Lunch: 'lunch',
  Dinner: 'dinner'
}

If u are limited to JavaScript, here's 2 solutions:

1. using Object.freeze

const Meal = Object.freeze({
  Breakfast: 'breakfast',
  Lunch: 'lunch',
  Dinner: 'dinner'
})

This introduces runtime restriction though.

2. using JSDoc /** @type {const} */

const Meal = /** @type {const} */ ({
  Breakfast: 'breakfast',
  Lunch: 'lunch',
  Dinner: 'dinner'
})

see: https://stackoverflow.com/questions/64559624/jsdoc-equivalent-to-typescripts-as-const