src/sass/parse.js
function checkVariable(i) {
  const start = i;
  let l;

  if (i >= tokensLength) return 0;

  // Skip `$`.
  if (tokens[i].type === TokenType.DollarSign) i++;
  else return 0;

  if (l = checkIdent(i)) i += l;
  else return 0;

  return i - start;
}
function checkVariable(i) {
  const start = i;
  let l;

  if (i >= tokensLength) return 0;

  // Skip `$`.
  if (tokens[i].type === TokenType.DollarSign) i++;
  else return 0;

  if (l = checkIdent(i)) i += l;
  else return 0;

  return i - start;
}
function checkVariable ( i ) { const start = i ; let l ; if ( i >= tokensLength ) return 0 ; // Skip `$`. if ( tokens [ i ] . type === TokenType . DollarSign ) i ++ ; else return 0 ; if ( l = checkIdent ( i ) ) i += l ; else return 0 ; return i - start ; }
Check if token is part of a variable
@param {number} i Token's index number
@return {number} Length of the variable
Check if token is part of a variable