Why does this tagged template helper drop substitutions after the first one?

programming web dev
1

I’m building a tiny tagged template helper that should interleave strings and values, but only the first substitution shows up. What am I indexing wrong here?

function join(strings, ...values) {
  let out = '';
  for (let i = 0; i < values.length; i++) {
    out += strings[i] + values[0];
  }
  return out + strings[strings.length - 1];
}

console.log(join`A:${1}, B:${2}, C:${3}`);

Expected: A:1, B:2, C:3
Actual: A:1, B:1, C:1

Why does this happen, and what’s the correct way to combine strings and values in a tag function?

Ellen

2

You’re always reading values[0], so every slot reuses the first substitution.

BayMax