[javascript] Hash table in JavaScript

I am using a hash table in JavaScript, and I want to show the values of the following in a hash table

one   -[1,10,5]
two   -[2]
three -[3, 30, 300, etc.]

I have found the following code. It works for the following data.

   one  -[1]
   two  -[2]
   three-[3]

How do I assign one-[1,2] values to a hash table and how do I access it?

<script type="text/javascript">
    function Hash()
    {
        this.length = 0;
        this.items = new Array();
        for (var i = 0; i < arguments.length; i += 2) {
            if (typeof(arguments[i + 1]) != 'undefined') {
                this.items[arguments[i]] = arguments[i + 1];
                this.length++;
            }
        }

        this.removeItem = function(in_key)
        {
            var tmp_value;
            if (typeof(this.items[in_key]) != 'undefined') {
                this.length--;
                var tmp_value = this.items[in_key];
                delete this.items[in_key];
            }
            return tmp_value;
        }

        this.getItem = function(in_key) {
            return this.items[in_key];
        }

        this.setItem = function(in_key, in_value)
        {
            if (typeof(in_value) != 'undefined') {
                if (typeof(this.items[in_key]) == 'undefined') {
                    this.length++;
                }

                this.items[in_key] = in_value;
            }
            return in_value;
        }

        this.hasItem = function(in_key)
        {
            return typeof(this.items[in_key]) != 'undefined';
        }
    }

    var myHash = new Hash('one',1,'two', 2, 'three',3 );

    for (var i in myHash.items) {
        alert('key is: ' + i + ', value is: ' + myHash.items[i]);
    }
</script>

How do I do it?

This question is related to javascript hashtable

The answer is


The Javascript interpreter natively stores objects in a hash table. If you're worried about contamination from the prototype chain, you can always do something like this:

// Simple ECMA5 hash table
Hash = function(oSource){
  for(sKey in oSource) if(Object.prototype.hasOwnProperty.call(oSource, sKey)) this[sKey] = oSource[sKey];
};
Hash.prototype = Object.create(null);

var oHash = new Hash({foo: 'bar'});
oHash.foo === 'bar'; // true
oHash['foo'] === 'bar'; // true
oHash['meow'] = 'another prop'; // true
oHash.hasOwnProperty === undefined; // true
Object.keys(oHash); // ['foo', 'meow']
oHash instanceof Hash; // true

If all you want to do is store some static values in a lookup table, you can use an Object Literal (the same format used by JSON) to do it compactly:

var table = { one: [1,10,5], two: [2], three: [3, 30, 300] }

And then access them using JavaScript's associative array syntax:

alert(table['one']);    // Will alert with [1,10,5]
alert(table['one'][1]); // Will alert with 10

If all you want to do is store some static values in a lookup table, you can use an Object Literal (the same format used by JSON) to do it compactly:

var table = { one: [1,10,5], two: [2], three: [3, 30, 300] }

And then access them using JavaScript's associative array syntax:

alert(table['one']);    // Will alert with [1,10,5]
alert(table['one'][1]); // Will alert with 10

The Javascript interpreter natively stores objects in a hash table. If you're worried about contamination from the prototype chain, you can always do something like this:

// Simple ECMA5 hash table
Hash = function(oSource){
  for(sKey in oSource) if(Object.prototype.hasOwnProperty.call(oSource, sKey)) this[sKey] = oSource[sKey];
};
Hash.prototype = Object.create(null);

var oHash = new Hash({foo: 'bar'});
oHash.foo === 'bar'; // true
oHash['foo'] === 'bar'; // true
oHash['meow'] = 'another prop'; // true
oHash.hasOwnProperty === undefined; // true
Object.keys(oHash); // ['foo', 'meow']
oHash instanceof Hash; // true

You could use my JavaScript hash table implementation, jshashtable. It allows any object to be used as a key, not just strings.


If all you want to do is store some static values in a lookup table, you can use an Object Literal (the same format used by JSON) to do it compactly:

var table = { one: [1,10,5], two: [2], three: [3, 30, 300] }

And then access them using JavaScript's associative array syntax:

alert(table['one']);    // Will alert with [1,10,5]
alert(table['one'][1]); // Will alert with 10

You could use my JavaScript hash table implementation, jshashtable. It allows any object to be used as a key, not just strings.