How might window.btoa() be implemented in JS?

/** * @param {string} b * @returns {string} */ const btoa = (b) => { let s = ''; const bytes = new Uint8Array(b.split('').map(x => x.charCodeAt(0))); const ALPHABET_TABLE = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz01234567...