msub/src/msub.js.txt

Simple, dependency-free, localization-friendly string and date replacement method for String

/*****************************************************************************
 * msub.js
 * Copyright 2016-2017 Jim Pravetz. MIT License (MIT)
 *****************************************************************************/

var regNumber = new RegExp(/\d+/);
var useUppercase = false;
var useMoment = false;
var moment;
var subRegEx;
var extRegEx;

// Convert uppercase with underscores to camelcase, eg. USE_STRING to useString
function convertKey(s) {
  if (useUppercase) {
    s = s
      .split('_')
      .map(function(word) {
        return word.charAt(0).toUpperCase() + word.slice(1);
      })
      .join('');
    return s.charAt(0).toLowerCase() + s.slice(1);
  }
  return s;
}

/**
 * Replace all instances of a ${prop} in this string with a value.
 * Note that any instances of ${prop in your string will be replaced, if it is found in the args
 * list. This limits your use of "${some-text}" to 'some-text' that does not match the args list.
 * @param args {object|array|arguments}
 *              If an object: Key, value pair where all instances of ${key} are replaced with value.
 *              If a list of arguments: converted to array
 *              If an array: replaces {1}, {2}, {3}, etc. with first, second, third, etc arguments.
 * @returns {string} Returns s with all instances of args replaced
 */
String.prototype.msub = function(args) {
  if (!moment && useMoment) {
    moment = require('moment');
  }

  var s = this;

  if (args !== undefined && args !== null) {
    var isArray;

    if (args.constructor !== Object) {
      isArray = true;
      if (args.constructor !== Array) {
        args = Array.prototype.slice.call(arguments);
      }
    }

    var parts = s.match(subRegEx);
    if (parts && parts.length) {
      for (var pdx = 0; pdx < parts.length; pdx++) {
        var p = parts[pdx].match(extRegEx);
        if (p.length >= 2) {
          var key = p[1];
          var fn = p[3];
          var val;
          if (isArray && regNumber.test(key)) {
            val = args[parseInt(key, 10)];
          } else {
            val = args[convertKey(key)];
          }
          if (val instanceof Date) {
            if (fn && typeof val[fn] === 'function') {
              val = val[fn]();
            } else if (fn && useMoment && moment) {
              val = moment(val).format(fn);
            } else {
              val = val.toString();
            }
          }
          if (val !== undefined) {
            s = s.replace(p[0], val);
          }
        }
      }
    }
  }
  return s.toString();
};

module.exports = init = function(options) {
  options || (options = {});
  var open = '\\$\\{'; // for ${0} pattern
  var close = '\\}';
  var notClose = '[^\\}]+';
  var notDivOrClose = '[^\\}:]+';
  if (options.open === '{') {
    open = '\\{';
  }
  if (options.uppercase === true) {
    useUppercase = true;
  }
  if (options.moment === true) {
    useMoment = true;
  }
  subRegEx = new RegExp(open + notClose + close, 'g');
  extRegEx = new RegExp(
    open + '(' + notDivOrClose + ')' + '(:(' + notClose + '))?' + close
  );
};

init();