1const crypto = require('crypto');
2
3const secret = 'abcdefg';
4const hash = crypto.createHmac('sha256', secret)
5                   .update('I love cupcakes')
6                   .digest('hex');
7console.log(hash);
8// Prints:
9//   c0fa1bc00531bd78ef38c628449c5102aeabd49b5dc3a2a516ea6ea959d6658e
10

1require("crypto")
2  .createHash("sha256")
3  .update("Man oh man do I love node!")
4  .digest("hex");
5

1function HashTable(obj)
2{
3    this.length = 0;
4    this.items = {};
5    for (var p in obj) {
6        if (obj.hasOwnProperty(p)) {
7            this.items[p] = obj[p];
8            this.length++;
9        }
10    }
11
12    this.setItem = function(key, value)
13    {
14        var previous = undefined;
15        if (this.hasItem(key)) {
16            previous = this.items[key];
17          	return previous;
18        }
19        else {
20            this.length++;
21        }
22        this.items[key] = value;
23        return previous;
24    }
25
26    this.getItem = function(key) {
27        return this.hasItem(key) ? this.items[key] : undefined;
28    }
29
30    this.hasItem = function(key)
31    {
32        return this.items.hasOwnProperty(key);
33    }
34   
35    this.removeItem = function(key)
36    {
37        if (this.hasItem(key)) {
38            previous = this.items[key];
39            this.length--;
40            delete this.items[key];
41            return previous;
42        }
43        else {
44            return undefined;
45        }
46    }
47
48    this.keys = function()
49    {
50        var keys = [];
51        for (var k in this.items) {
52            if (this.hasItem(k)) {
53                keys.push(k);
54            }
55        }
56        return keys;
57    }
58
59    this.values = function()
60    {
61        var values = [];
62        for (var k in this.items) {
63            if (this.hasItem(k)) {
64                values.push(this.items[k]);
65            }
66        }
67        return values;
68    }
69
70    this.each = function(fn) {
71        for (var k in this.items) {
72            if (this.hasItem(k)) {
73                fn(k, this.items[k]);
74            }
75        }
76    }
77
78    this.clear = function()
79    {
80        this.items = {}
81        this.length = 0;
82    }
83}
84        

1var h = new Object(); // or just {}
2h['one'] = 1;
3h['two'] = 2;
4h['three'] = 3;
5
6// show the values stored
7for (var k in h) {
8    // use hasOwnProperty to filter out keys from the Object.prototype
9    if (h.hasOwnProperty(k)) {
10        alert('key is: ' + k + ', value is: ' + h[k]);
11    }
12}
13