How to create a simple map using JavaScript JQuery

Question

How can you create the JavaScript JQuery equivalent of this Java code   Map map   new HashMap      Doesn t not have to be a hash map  any key value map is fine map put myKey1  myObj1   map put myKey2  myObj2     Repeat n times  function Object get k        return map get k

User · Answer

If you re not restricted to JQuery  you can use the prototype js framework   It has a class called Hash   You can even use JQuery  amp  prototype js together   Just type jQuery noConflict     var h   new Hash    h set  key    value    h get  key    h keys       returns an array of keys h values       returns an array of values

User · Answer

function Map         this keys   new Array        this data   new Object         this put   function  key  value            if  this data key     null                this keys push key                     this data key    value              this get   function  key            return this data key               this remove   function  key            this keys remove key           this data key    null              this each   function  fn            if  typeof fn     function                 return                    var len   this keys length          for  var i   0  i  lt  len  i                  var k   this keys i               fn k  this data k   i                         this entrys   function              var len   this keys length          var entrys   new Array len           for  var i   0  i  lt  len  i                  entrys i                      key  this keys i                   value  this data i                                   return entrys              this isEmpty   function              return this keys length    0              this size   function              return this keys length

User · Answer

This is an old question  but because the existing answers could be very dangerous  I wanted to leave this answer for future folks who might stumble in here     The answers based on using an Object as a HashMap are broken and can cause extremely nasty consequences if you use anything other than a String as the key  The problem is that Object properties are coerced to Strings using the  toString method  This can lead to the following nastiness   function MyObject name      this name   name     var key1   new MyObject  one    var key2   new MyObject  two     var map       map key1    1  map key2    2    If you were expecting that Object would behave in the same way as a Java Map here  you would be rather miffed to discover that map only contains one entry with the String key  object Object     gt  JSON stringify map      object Object    2    This is clearly not a replacement for Java s HashMap  Bizarrely  given it s age  Javascript does not currently have a general purpose map object  There is hope on the horizon  though  https   developer mozilla org en-US docs Web JavaScript Reference Global Objects Map although a glance at the Browser Compatability table there will show that this isn t ready to used in general purpose web apps yet   In the meantime  the best you can do is    Deliberately use Strings as keys  I e  use explicit strings as keys rather than relying on the implicit  toString-ing of the keys you use  Ensure that the objects you are using as keys have a well-defined  toString   method that suits your understanding of uniqueness for these objects  If you cannot don t want to change the  toString of the key Objects  when storing and retrieving the entries  convert the objects to a string which represents your understanding of uniqueness  E g  map toUniqueString key1     1   Sometimes  though  that is not possible  If you want to map data based on  for example File objects  there is no reliable way to do this because the attributes that the File object exposes are not enough to ensure its uniqueness   You may have two File objects that represent different files on disk  but there is no way to distinguish between them in JS in the browser   In these cases  unfortunately  all that you can do is refactor your code to eliminate the need for storing these in a may  perhaps  by using an array instead and referencing them exclusively by index

User · Answer

Just use plain objects   var map     key1   value1   key2   value2    function get k     return map k

User · Answer

Edit  Out of date answer  ECMAScript 2015  ES6  standard javascript has a Map implementation  read here for more info  https   developer mozilla org en-US docs Web JavaScript Reference Global Objects Map  var map   new Object       or var map       map myKey1    myObj1  map myKey2    myObj2   function get k        return map k        map myKey1     get myKey1

User · Answer

var map     myKey1  myObj1   mykey2  myObj2      You don t need any get function  just use map  mykey1

[javascript] How to create a simple map using JavaScript/JQuery

Examples related to javascript

Examples related to jquery

Examples related to hashmap