-
Notifications
You must be signed in to change notification settings - Fork 1
Expand file tree
/
Copy pathJS-Data-Types.html
More file actions
421 lines (347 loc) 路 20.2 KB
/
Copy pathJS-Data-Types.html
File metadata and controls
421 lines (347 loc) 路 20.2 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>JS Data Types</title>
</head>
<style>
* {
font-family: Arial, Helvetica, sans-serif;
}
table {
font-family: arial, sans-serif;
border-collapse: collapse;
width: 50%;
}
td,
th {
border: 1px solid #dddddd;
text-align: left;
padding: 8px;
}
tr:nth-child(even) {
background-color: #dddddd;
}
code[class*="language-"],
pre[class*="language-"] {
color: black;
background: none;
background-color: rgba(0, 0, 0, 0);
font-family: Consolas, Monaco, "Andale Mono", "Ubuntu Mono", monospace;
font-size: 1em;
text-align: left;
white-space: pre;
word-spacing: normal;
word-break: normal;
word-wrap: normal;
line-height: 1.5;
-moz-tab-size: 4;
-o-tab-size: 4;
tab-size: 4;
-webkit-hyphens: none;
-moz-hyphens: none;
-ms-hyphens: none;
hyphens: none;
}
:not(pre) > code[class*="language-"]::after,
pre[class*="language-"]::after {
right: 0.75em;
left: auto;
-webkit-transform: rotate(2deg);
-moz-transform: rotate(2deg);
-ms-transform: rotate(2deg);
-o-transform: rotate(2deg);
transform: rotate(2deg);
}
pre[class*="language-"]::before,
pre[class*="language-"]::after {
content: "";
z-index: -2;
display: block;
position: absolute;
bottom: 0.75em;
left: 0.18em;
width: 40%;
height: 20%;
max-height: 13em;
-webkit-transform: rotate(-2deg);
-moz-transform: rotate(-2deg);
-ms-transform: rotate(-2deg);
-o-transform: rotate(-2deg);
transform: rotate(-2deg);
}
:not(pre) > code[class*="language-"],
pre[class*="language-"] {
background-color: #fdfdfd;
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
margin-bottom: 1em;
}
pre[class*="language-"] {
position: relative;
margin: 0.5em 0;
margin-bottom: 0.5em;
overflow: visible;
padding: 0;
}
code[class*="language-"],
pre[class*="language-"] {
color: black;
background: none;
background-color: rgba(0, 0, 0, 0);
font-family: Consolas, Monaco, "Andale Mono", "Ubuntu Mono", monospace;
font-size: 1em;
text-align: left;
white-space: pre;
word-spacing: normal;
word-break: normal;
word-wrap: normal;
line-height: 1.5;
-moz-tab-size: 4;
-o-tab-size: 4;
tab-size: 4;
-webkit-hyphens: none;
-moz-hyphens: none;
-ms-hyphens: none;
hyphens: none;
}
pre {
display: block;
font-size: 87.5%;
color: #212529;
}
pre {
margin-top: 0;
margin-bottom: 1rem;
overflow: auto;
-ms-overflow-style: scrollbar;
}
code,
kbd,
pre,
samp {
font-family: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono",
"Courier New", monospace;
font-size: 1em;
}
pre[class*="language-"] > code {
position: relative;
border-left: 10px solid #358ccb;
box-shadow: -1px 0px 0px 0px #358ccb, 0px 0px 0px 1px #dfdfdf;
background-color: #fdfdfd;
background-image: linear-gradient(
transparent 50%,
rgba(69, 142, 209, 0.04) 50%
);
background-size: 3em 3em;
background-origin: content-box;
background-attachment: local;
}
code[class*="language"] {
max-height: inherit;
height: inherit;
padding: 0 1em;
display: block;
overflow: auto;
}
code[class*="language-"],
pre[class*="language-"] {
color: black;
background: none;
background-color: rgba(0, 0, 0, 0);
background-attachment: scroll;
background-image: none;
background-size: auto;
background-origin: padding-box;
font-family: Consolas, Monaco, "Andale Mono", "Ubuntu Mono", monospace;
font-size: 1em;
text-align: left;
white-space: pre;
word-spacing: normal;
word-break: normal;
word-wrap: normal;
line-height: 1.5;
-moz-tab-size: 4;
-o-tab-size: 4;
tab-size: 4;
-webkit-hyphens: none;
-moz-hyphens: none;
-ms-hyphens: none;
hyphens: none;
}
pre code {
font-size: inherit;
color: inherit;
word-break: normal;
}
code {
font-size: 87.5%;
color: #e83e8c;
word-wrap: break-word;
}
code,
kbd,
pre,
samp {
font-family: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono",
"Courier New", monospace;
font-size: 1em;
}
*,
::after,
::before {
box-sizing: border-box;
}
</style>
<body>
<p>
JavaScript provides different data types to hold different types of
values. There are two types of data types in JavaScript.
</p>
<ol>
<li>Primitive data type</li>
<li>Non-primitive (reference) data type</li>
</ol>
<p>
JavaScript is a dynamic type language, means you don't need to specify
type of the variable because it is dynamically used by JavaScript engine.
You need to use var here to specify the data type. It can hold any type of
values such as numbers, strings etc. For example:
</p>
<ol>
<li>var a=40; holding number</li>
<li>var b="Hamza"; holding string</li>
</ol>
<hr />
<h1>JavaScript primitive data types</h1>
<p>
There are five types of primitive data types in JavaScript. They are as
follows:
</p>
<table>
<tr>
<th>Data Type</th>
<th>Description</th>
</tr>
<tr>
<td>String</td>
<td>represents sequence of characters e.g. "hello"</td>
</tr>
<tr>
<td>Number</td>
<td>represents numeric values e.g. 100</td>
</tr>
<tr>
<td>Boolean</td>
<td>represents boolean value either false or true</td>
</tr>
<tr>
<td>Undefined</td>
<td>represents undefined value</td>
</tr>
<tr>
<td>Null</td>
<td>represents null i.e. no value at all</td>
</tr>
</table>
<hr />
<h1>JavaScript non-primitive data types</h1>
<p>The non-primitive data types are as follows:</p>
<table>
<tr>
<th>Data Type</th>
<th>Description</th>
</tr>
<tr>
<td>Object</td>
<td>represents instance through which we can access members</td>
</tr>
<tr>
<td>Array</td>
<td>represents group of similar values</td>
</tr>
<tr>
<td>RegExp</td>
<td>represents regular expression</td>
</tr>
</table>
<hr />
<h3>Example:</h3>
<pre
class="language-markup"
tabindex="0"
><code class="language-markup"><span class="token doctype"><span class="token punctuation"><!</span><span class="token doctype-tag">DOCTYPE</span> <span class="token name">html</span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation"><</span>html</span> <span class="token attr-name">lang</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>en<span class="token punctuation">"</span></span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation"><</span>head</span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation"><</span>meta</span> <span class="token attr-name">charset</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>UTF-8<span class="token punctuation">"</span></span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation"><</span>meta</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>viewport<span class="token punctuation">"</span></span> <span class="token attr-name">content</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>width=device-width, initial-scale=1.0<span class="token punctuation">"</span></span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation"><</span>meta</span> <span class="token attr-name">http-equiv</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>X-UA-Compatible<span class="token punctuation">"</span></span> <span class="token attr-name">content</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>ie=edge<span class="token punctuation">"</span></span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation"><</span>title</span><span class="token punctuation">></span></span>JavaScript<span class="token tag"><span class="token tag"><span class="token punctuation"></</span>title</span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation"><</span>script</span><span class="token punctuation">></span></span><span class="token script"><span class="token language-javascript">
<span class="token comment">/* String Data Type */</span>
<span class="token keyword">var</span> a <span class="token operator">=</span> <span class="token string">"Hello World"</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span>a<span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token string">"<br>"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token keyword">typeof</span> a<span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token string">"<br><br>"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">/* Number Data Type */</span>
<span class="token keyword">var</span> b <span class="token operator">=</span> <span class="token number">25</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span>b<span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token string">"<br>"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token keyword">typeof</span> b<span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token string">"<br><br>"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">/* Boolean Data Type */</span>
<span class="token keyword">var</span> c <span class="token operator">=</span> <span class="token boolean">true</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span>c<span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token string">"<br>"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token keyword">typeof</span> c<span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token string">"<br><br>"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">/* Array Data Type */</span>
<span class="token keyword">var</span> d<span class="token operator">=</span> <span class="token punctuation">[</span><span class="token string">"HTML"</span><span class="token punctuation">,</span><span class="token string">"CSS"</span><span class="token punctuation">,</span><span class="token string">"JS"</span><span class="token punctuation">]</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span>d<span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token string">"<br>"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token keyword">typeof</span> d<span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token string">"<br><br>"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">/* Object Data Type */</span>
<span class="token keyword">var</span> x<span class="token operator">=</span> <span class="token punctuation">{</span><span class="token literal-property property">first</span><span class="token operator">:</span><span class="token string">"Jane"</span><span class="token punctuation">,</span><span class="token literal-property property">last</span><span class="token operator">:</span><span class="token string">"Doe"</span><span class="token punctuation">}</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span>x<span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token string">"<br>"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token keyword">typeof</span> x<span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token string">"<br><br>"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">/* Null Data Type */</span>
<span class="token keyword">var</span> y <span class="token operator">=</span> <span class="token keyword">null</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span>y<span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token string">"<br>"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token keyword">typeof</span> y<span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token string">"<br><br>"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token comment">/* undefined Data Type */</span>
<span class="token keyword">var</span> z<span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span>z<span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token string">"<br>"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token keyword">typeof</span> z<span class="token punctuation">)</span><span class="token punctuation">;</span>
document<span class="token punctuation">.</span><span class="token function">write</span><span class="token punctuation">(</span><span class="token string">"<br><br>"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
</span></span><span class="token tag"><span class="token tag"><span class="token punctuation"></</span>script</span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation"></</span>head</span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation"><</span>body</span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation"></</span>body</span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation"></</span>html</span><span class="token punctuation">></span></span></code></pre>
</body>
<script>
let a = "Hamza Khan Lodhi";
document.write(a + " " + typeof a + "<br><br>");
let b = 56964;
document.write(b + " " + typeof b + "<br><br>");
let c = true;
document.write(c + " " + typeof c + "<br><br>");
let d = ["html", "css", "js"];
document.write(d + " " + typeof d + "<br><br>");
let e = { first: "hamza", second: "umar" };
document.write(e + " " + typeof e + "<br><br>");
let f = null;
document.write(f + " " + typeof f + "<br><br>");
let g;
document.write(g + " " + typeof g + "<br><br>");
</script>
</html>