stringcalculator.js

function add(string) {
  if (!string) {
    return 0;
  }
  let delimiter = /[\n,]+/;
  if (string.startsWith('//[')) {
    const lines = string.split('\n');
    delimiter = lines[0].replace(/\/\/\[|\]/g, '');
    // const things = lines[0].replace('//', '');
    // const delimiters = things.match(/\[(.*?)\]/g); // Can't quite nail the regex on this one
    // console.log(delimiters);
    // delimiter = new RegExp(delimiters.join('|'));
    lines.shift();
    string = lines.join('\n');
  }
  const numbers = string.split(delimiter);
  const negatives = numbers.filter((number) => number < 0);
  if (negatives.length) {
    throw (`Negatives not allowed: ${negatives.join(',')}`);
  }
  return numbers.reduce((a, b) => {
    a = a > 1000 ? 0 : a;
    b = b > 1000 ? 0 : b;
    return parseInt(a) + parseInt(b);
  }, 0);
}

function tests() {
  test(add(''), 0);
  test(add('1'), 1);
  test(add('2'), 2);
  test(add('1,2'), 3);
  test(add('1,3'), 4);
  test(add('2,3'), 5);
  test(add('2,3,4'), 9);
  test(add('2,3,4,5'), 14);
  test(add('2,3,4\n6'), 15);
  test(add('//[;]\n2;3;4;7'), 16);
  // test for negatives
  test(add('2,1001'), 2);
  test(add('1001,2'), 2);
  test(add('//[***]\n1***2***3'), 6);
  test(add('//[*%*]\n1*%*2*%*3'), 6);
  // test(add('//[***][%%%]\n1%%%2***5'), 8); // Can't quite nail the regex on this one
  console.log('All tests pass');
}

function test(actual, expectation) {
  if (expectation !== actual) {
    throw (`${actual} does not equal ${expectation}`);
  }
}

tests();