array-utils.js

/**
 * isEven
 * @param {number}
 */
export function isEven(num) {
  return num % 2 === 0;
}

/**
 * Count Items
 * @param {array}
 */
export function countItems(items) {
  if (items) {
    return items.length;
  }
}

/** 
 * Is Last Item 
 * @param {array}
 */
export function isLastItem(index, arry) {
  return index === arry.length - 1;
}

currency-utils.js

/**
 * Format Currency
 * @param {string} priceStr - price string
 * @param {string} locale - locale string
 * @param {string} currency - currency type string
 */
export function formatCurrency(priceStr, locale = 'en-US', currency = 'USD') {
  if (!priceStr) return;

  const price = parseInt(priceStr);
  return price.toLocaleString(locale, {
    style: 'currency',
    currency: currency
  });
}

date-utils.js

/**
 * Get a date, x number of days from Today
 * @param {number} days - days to add
 * @param {string} weekdayStyle - ex:'short', 'long'
 * @param {string} monthStyle - ex: 'short', 'long'
 * @param {bool} hasYear - output year
 */
export function getFutureDate(
  days,
  weekdayStyle = 'long',
  monthStyle = 'long'
) {
  const today = new Date();
  today.setDate(today.getDate() + days);

  const options = {
    ...(weekdayStyle && { weekday: weekdayStyle }),
    ...(monthStyle && { month: monthStyle }),
    day: 'numeric'
  };

  return today.toLocaleString('en-us', options);
}

string-utils.js

/**
 * Capitalize String
 * @param {string}
 */
export function capitalize(str) {
  return str.replace(/^\w/, c => c.toUpperCase());
}


/**
 * Convert string to Sentence Case
 * @param {string}
 */
export function sentenceCase(str) {
  const caps = str.replace(/^\w/, c => c.toUpperCase());
  return caps.replace(/_/g, ' ').replace(/-/g, '');
}

/**
 * dashify
 * Formats string to an ID friendly version,
 * replacing whitespace with dashes and lowercasing
 */
export function dashify(str) {
  const dashes = str.replace(/\s/g, '-');
  return dashes.toLowerCase();
}

/**
 * Text Elippser
 * @param {string} - content string
 * @param {number} - number of chars before ellipse
 */
export function ellipseText(str, maxChars) {
  return str.length > maxChars ? `${str.substr(0, maxChars)}...` : str;
}

/**
 * String Decoder
 * @param {String}
 */
export function decode(str) {
  return str.replace(/&#(\d+);/g, (match, dec) => {
    String.fromCharCode(dec);
  });
}

/** 
 * Count number of words 
 * @param {String}
 */
export function countWords(str) {
  return str.split(/\s+/).length;
}

type-utils.js

/** 
 * Is Object 
 */
export function isObject(value) {
   return value && typeof value === "object" && value.constructor === Object;
}

/** 
 * Is Array
 */
export function isArray(value) {
   // https://webbjocke.com/javascript-check-data-types/#javascript-array
   return value && typeof value === "object" && value.constructor === Array;
}