I'm doing a Scrabble challenge but I'm stuck

Question

I have to create this JS scrabble but I'm having problems adding up each values of the word to make a total points, for example if the word is 'hello' it should the sum will be 8.. And also I need my object to return the total value of the word, not the [object Object] ..

const scores = {
  a: 1,
  e: 1,
  i: 1,
  o: 1,
  u: 1,
  l: 1,
  n: 1,
  r: 1,
  s: 1,
  t: 1,
  d: 2,
  g: 2,
  b: 3,
  c: 3,
  m: 3,
  p: 3,
  f: 4,
  h: 4,
  v: 4,
  w: 4,
  y: 4,
  k: 5,
  j: 8,
  x: 8,
  q: 10,
  z: 10
}

const notValid = 'Input not valid:'
const validWord = 'Great, your point is:'
const singleValue = scores

function scrabble(letter) {
  if (typeof letter !== 'string') {
    return `${notValid} 0`
  } else if (letter === '!' || letter === '.') {
    return `${notValid} 0`
  } else if (letter === ' ' || letter === '\t\n') {
    return `${notValid} 0`
  } else if (letter === ',' || letter === '?') {
    return `${notValid} 0`
  } else if (letter === ',' || letter === null) {
    return `${notValid} 0`
  } else {
    return `${validWord} ${singleValue} `
  }
}

function loopLetters(word) {
  let result = 0
  for (let i = 0; i <= word.length; i++) {
    result += [word[i]]
    console.log(scores[word[i]])
  }
  return result
}

console.log('--', loopLetters('hello'))

console.log(scrabble(loopLetters('hello')))```

My console.log results are:
4
1
1
1
1
undefined
-- 0hello
4
1
1
1
1
undefined
Great, your point is: [object Object]