Parsing error: Unexpected token (after computed property name)

[patrickroberts]

function characterRange (minCharacter, maxCharacter) {
  const lower = minCharacter.charCodeAt(0)
  const upper = maxCharacter.charCodeAt(0)

  return Array(upper - lower + 1)
    .fill()
    .map((_, index) => String.fromCharCode(lower + index))
    .join('')
}

const base64 =
  characterRange('A', 'Z') +
  characterRange('a', 'z') +
  characterRange('0', '9') +
  '+/'

const unbase64 = Array.from(base64)
  .reduce((table, character, index) => {
    table[character.charCodeAt(0)] = index
    return table
  }), { ['='.charCodeAt(0)]: 64 })
                             ^ line 21:column 30

Generates an error:

21:30 - Parsing error: Unexpected token 64 (null)

I believe that for some reason standard@10.0.3 fails to parse computed property names, as changing the accumulator object literal of Array#reduce() to any variation of a computed property name causes the same error.

Is this a bug?

[patrickroberts]

Nevermind, I just noticed I had an extra closing parenthesis on the same line... sorry to bother.