blob: cb45e53932ac97b5efa663969e3584bf30ad183f (
plain)
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
|
# Hello world
## Concepts
- Deno can run JavaScript or TypeScript out of the box with no additional tools
or config required.
## Overview
Deno is a secure runtime for both JavaScript and TypeScript. As the hello world
examples below highlight the same functionality can be created in JavaScript or
TypeScript, and Deno will execute both.
## JavaScript
In this JavaScript example the message `Hello [name]` is printed to the console
and the code ensures the name provided is capitalized.
**Command:** `deno run hello-world.js`
```js
/**
* hello-world.js
*/
function capitalize(word) {
return word.charAt(0).toUpperCase() + word.slice(1);
}
function hello(name) {
return "Hello " + capitalize(name);
}
console.log(hello("john"));
console.log(hello("Sarah"));
console.log(hello("kai"));
/**
* Output:
*
* Hello John
* Hello Sarah
* Hello Kai
**/
```
## TypeScript
This TypeScript example is exactly the same as the JavaScript example above, the
code just has the additional type information which TypeScript supports.
The `deno run` command is exactly the same, it just references a `*.ts` file
rather than a `*.js` file.
**Command:** `deno run hello-world.ts`
```ts
/**
* hello-world.ts
*/
function capitalize(word: string): string {
return word.charAt(0).toUpperCase() + word.slice(1);
}
function hello(name: string): string {
return "Hello " + capitalize(name);
}
console.log(hello("john"));
console.log(hello("Sarah"));
console.log(hello("kai"));
/**
* Output:
*
* Hello John
* Hello Sarah
* Hello Kai
**/
```
|
