define(['exports'], function (exports) {
  'use strict';

  exports.__esModule = true;
  exports.extend = extend;

  // Older IE versions do not directly support indexOf so we must implement our own, sadly.
  exports.indexOf = indexOf;
  exports.escapeExpression = escapeExpression;
  exports.isEmpty = isEmpty;
  exports.blockParams = blockParams;
  exports.appendContextPath = appendContextPath;
  var escape = {
    '&': '&amp;',
    '<': '&lt;',
    '>': '&gt;',
    '"': '&quot;',
    '\'': '&#x27;',
    '`': '&#x60;'
  };

  var badChars = /[&<>"'`]/g,
      possible = /[&<>"'`]/;

  function escapeChar(chr) {
    return escape[chr];
  }

  function extend(obj /* , ...source */) {
    for (var i = 1; i < arguments.length; i++) {
      for (var key in arguments[i]) {
        if (Object.prototype.hasOwnProperty.call(arguments[i], key)) {
          obj[key] = arguments[i][key];
        }
      }
    }

    return obj;
  }

  var toString = Object.prototype.toString;

  exports.toString = toString;
  // Sourced from lodash
  // https://github.com/bestiejs/lodash/blob/master/LICENSE.txt
  /*eslint-disable func-style, no-var */
  var isFunction = function isFunction(value) {
    return typeof value === 'function';
  };
  // fallback for older versions of Chrome and Safari
  /* istanbul ignore next */
  if (isFunction(/x/)) {
    exports.isFunction = isFunction = function (value) {
      return typeof value === 'function' && toString.call(value) === '[object Function]';
    };
  }
  var isFunction;
  exports.isFunction = isFunction;
  /*eslint-enable func-style, no-var */

  /* istanbul ignore next */
  var isArray = Array.isArray || function (value) {
    return value && typeof value === 'object' ? toString.call(value) === '[object Array]' : false;
  };exports.isArray = isArray;

  function indexOf(array, value) {
    for (var i = 0, len = array.length; i < len; i++) {
      if (array[i] === value) {
        return i;
      }
    }
    return -1;
  }

  function escapeExpression(string) {
    if (typeof string !== 'string') {
      // don't escape SafeStrings, since they're already safe
      if (string && string.toHTML) {
        return string.toHTML();
      } else if (string == null) {
        return '';
      } else if (!string) {
        return string + '';
      }

      // Force a string conversion as this will be done by the append regardless and
      // the regex test will do this transparently behind the scenes, causing issues if
      // an object's to string has escaped characters in it.
      string = '' + string;
    }

    if (!possible.test(string)) {
      return string;
    }
    return string.replace(badChars, escapeChar);
  }

  function isEmpty(value) {
    if (!value && value !== 0) {
      return true;
    } else if (isArray(value) && value.length === 0) {
      return true;
    } else {
      return false;
    }
  }

  function blockParams(params, ids) {
    params.path = ids;
    return params;
  }

  function appendContextPath(contextPath, id) {
    return (contextPath ? contextPath + '.' : '') + id;
  }
});