Anchor - A URL parsing utility

anchor.js

/**
 * Anchor - A URL parsing utility
 *
 * Copyright 2012, Matthew Cobbs
 * MIT licensed
 *
 * Methods:
 * 
 * getSearchVars - returns a key-value object with the parameters in the URL search
 * setSearchVars(o) - sets parameters using a key-value object in the URL search
 * setSearchVar(key, val) - sets the key parameter to val in the URL search
 * delSearchVar(key) - deletes the key parameter from the URL search
 * 
 * getHashVars - returns a key-value object with the parameters in the URL hash
 * setHashVars(o) - sets parameters using a key-value object in the URL hash
 * setHashVar(key, val) - sets the key parameter to val in the URL hash
 * delHashVar(key) - deletes the key parameter from the URL hash
 * 
 * Usage:
 * 
 * var a = new Anchor("http://www.example.com?fruit=banana&pie=apple#page=1");
 * a.href;   // "http://www.example.com?fruit=banana&pie=apple#page=1";
 * a.search; // "?fruit=banana&pie=apple"
 * a.hash;   // "#page=1"
 * 
 * a.getSearchVars(); // {"fruit": "banana", "pie": "apple"}
 * a.getHashVars();   // {"page": "1"}
 * 
 * a.setSearchVars({fruit: "pear", type: "test"});
 * a.href; // "http://www.example.com/?fruit=pear&pie=apple&type=test#page=1"
 * 
 * a.setHashVars({page: 2});
 * a.href; // "http://www.example.com/?fruit=pear&pie=apple&type=test#page=2"
 * 
 * a.setSearchVar("type", "live");
 * a.href; // "http://www.example.com/?fruit=pear&pie=apple&type=live#page=2"
 * 
 * a.setHashVar("page", 3);
 * a.href; // "http://www.example.com/?fruit=pear&pie=apple&type=live#page=3"
 * 
 * a.delSearchVar("type");
 * a.href; // "http://www.example.com/?fruit=pear&pie=apple#page=3"
 * 
 * a.delHashVar("page");
 * a.href; // "http://www.example.com/?fruit=pear&pie=apple#"
 */
var Anchor = window.top.Anchor = (function (window, document, undefined) {
  
  "use strict";
  
  var anchor = document.createElement("a");
  
  // type check
  var isObject = function (o) {
    return typeof o === "object" && o !== null;
  };
  
  var isArray = function (o) {
    return Object.prototype.toString.call(o) === "[object Array]";
  };
  
  // object extend
  var extend = function (o, o2) {
    var i;
    
    for (i in o2) {
      if (o2.hasOwnProperty(i)) {
        o[i] = o2[i];
      }
    }
    
    return o;
  };
  
  // append a key-value pair to an object
  var append = function (o, key, val) {
    if (isObject(o) && o.hasOwnProperty(key)) {
      if (isArray(o[key])) {
        o[key].push(val);
      } else {
        o[key] = [o[key], val];
      }          
    } else {
      o[key] = val;
    }
  };
  
  // turn a key value pair into a string
  var stringify = function (key, val) {
    var s = "", i, l;
    
    if (isArray(val)) {
      for (i = 0, l = val.length; i < l; i++) {
        s += "&" + key + "=" + val[i];
      }
    } else {
      s += "&" + key + "=" + val;
    }
    
    return s;
  };
  
  // update the value of a key
  var update = function (o, key, val) {
    if (isObject(o)) {
      if (val === undefined) {
        delete o[key];
      } else {
        o[key] = val;
      }
    }
  };
  
  // turn a search or hash into an object
  var toObject = function (s) {
    var list = s && s.split("&") || [],
        o = {}, i, l, pair;
    
    for (i = 0, l = list.length; i < l; i++) {
      pair = list[i].split("=");
      append(o, pair[0], pair[1]);
    }
    
    return o;
  };
  
  // turn an object into a str for search or hash
  var toString = function (o) {
    var s = "", i;
    
    for (i in o) {
      if (o.hasOwnProperty(i)) {
        s += stringify(i, o[i]);
      }
    }
    
    return s.replace(/^\&/, "");
  };
  
  // cache
  var cache = {};
  
  // get search and hash vars  
  var getUrlVars = function (type) {
    var vars;
    
    if (cache.hasOwnProperty(this.href)) {
      vars = cache[this.href];
    } else {
      vars = {
        search: toObject(this.search.replace(/^\?/, "")),
        hash: toObject(this.hash.replace(/^\#/, ""))
      };
    }
    
    cache[this.href] = vars;
    return type ? vars[type] : vars;
  };
  
  // set search and hash vars  
  var setUrlVars = function (type, o) {
    var vars = getUrlVars.call(this, type),
        i;
    
    for (i in o) {
      if (o.hasOwnProperty(i)) {
        update(vars, i, o[i]);
      }
    }
    
    return toString(vars);
  };
  
  // public interface
  var methods = {
    
    getSearchVars: function () {
      return getUrlVars.call(this, "search");
    },
    
    getHashVars: function () {
      return getUrlVars.call(this, "hash");
    },
    
    setSearchVars: function (o) {
      this.search = setUrlVars.call(this, "search", o);
      return this;
    },   
    
    setSearchVar: function (key, val) {
      var o = {};
      o[key] = val;
      return this.setSearchVars(o);
    },    
    
    setHashVars: function (o) {
      this.hash = setUrlVars.call(this, "hash", o);
      return this;
    },    
    
    setHashVar: function (key, val) {
      var o = {};
      o[key] = val;
      return this.setHashVars(o);
    },
    
    delSearchVar: function (key) {
      return this.setSearchVar(key);
    },    
    
    delHashVar: function (key) {
      return this.setHashVar(key);
    }
    
  };
  
  // constructor and prototype
  var Anchor = function (href) {
    this.href = href;
  };
  
  Anchor.prototype = extend(anchor, methods);
  
  // return factory
  return function (href) {
    return new Anchor(href);
  };
  
})(window, document);