How many bytes in a JavaScript string?

console.info(
  new Blob(['😂']).size,                             // 4
  new Blob(['👍']).size,                             // 4
  new Blob(['😂👍']).size,                           // 8
  new Blob(['👍😂']).size,                           // 8
  new Blob(['I\'m a string']).size,                  // 12

  // from Premasagar correction of Lauri's answer for
  // strings containing lone characters in the surrogate pair range:
  // https://stackoverflow.com/a/39488643/6225838
  new Blob([String.fromCharCode(55555)]).size,       // 3
  new Blob([String.fromCharCode(55555, 57000)]).size // 4 (not 6)
);