JavaScript - Necesito ayuda

let movies = ["Las Crónicas de Narnia",

"Harry Potter y la Piedra Filosofal",

"El Señor de los Anillos",

"Fast and Furious 2",

"Jumanji"]

let arr = [];

let largest = "";

let bold = "";

movies.map(movie => {

  let m = movie.split(" ").join("")

  let number = m.length;

  arr.push(`${movie}[${number}]`)

  if (m.length > largest.length) {

    largest = m;

    bold = `${movie}[${number}]`

  }

});

var index = arr.indexOf(bold);

if (index !== -1) {

    arr[index] = bold.bold();

}

arr.map(item => console.log(item))

/*

Las Crónicas de Narnia[19]

<b>Harry Potter y la Piedra Filosofal[29]</b>

El Señor de los Anillos[19]

Fast and Furious 2[15]

Jumanji[7]

*/