String utility functions.

string.js

const upperCaseFirstLetter = string => {
  return string.charAt(0).toUpperCase() + string.slice(1);
};

const lowerCaseFirstLetter = string => {
  return string.charAt(0).toLowerCase() + string.slice(1);
};

const camelToDashCase = string => {
  return lowerCaseFirstLetter(string).replace(
    /([A-Z])/g,
    g => `-${g[0].toLowerCase()}`
  );
};

const stringStartsWith = (str, search, pos) => {
  return str.substr(!pos || pos < 0 ? 0 : +pos, search.length) === search;
};

const stringEndsWith = (str, search, length) => {
  if (length === undefined || length > str.length) {
    length = str.length;
  }
  return str.substring(length - search.length, length) === search;
};

const padString = (n, width, z = "0") => {
  n += "";
  return n.length >= width ? n : new Array(width - n.length + 1).join(z) + n;
};

const computeStringDifference = (a, b) => {
  let startCount = 0;
  let endCount = 0;
  const bigger = a.length > b.length ? a : b;
  for (let i = 0; i < bigger.length; i++) {
    if (a[i] === b[i]) {
      startCount++;
    } else {
      break;
    }
  }
  for (let i = 0; i < bigger.length; i++) {
    if (a[a.length - 1 - i] === b[b.length - 1 - i]) {
      endCount++;
    } else {
      break;
    }
  }
  return bigger.slice(startCount, bigger.length - endCount);
};

const removeCharAt = (str, index) => {
  return str.slice(0, index) + str.slice(index + 1);
};

const addCommasToNumber = number => {
  const withCommas = number
    .toString()
    .replace(/(\d)(?=(\d\d\d)+(?!\d))/g, "$1,");
  return withCommas;
};

export {
  padString,
  stringStartsWith,
  stringEndsWith,
  removeCharAt,
  upperCaseFirstLetter,
  lowerCaseFirstLetter,
  camelToDashCase,
  computeStringDifference,
  addCommasToNumber,
};