String Stuff

string-stuff.js

const replace = (word, index, replacement) => {
  return word.substr(0, index) + replacement + word.substr(index + replacement.length);
}

// another replace:
const replaceChar = (index, newChar, string) => {
  if (index < string.length) return `${string.substring(0, index)}${newChar}${string.substring(index + 1)}`
}

const differByCase = (c1, c2) => Math.abs(c1.charCodeAt(0) - c2.charCodeAt(0) === 32)

// makes a number from a number string, e.g. '100'
const makeNum = (string) => {
    let num = 0;

    for (let i = 0; i < string.length; i += 1) {
      const digit = string[i];
      if (isNaN(digit)) throw new Error('not a num!');
      num = +digit + (num * 10);
    }

    return num;
};