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67 lines
1.3 KiB
Markdown
67 lines
1.3 KiB
Markdown
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# Hello World
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Deno is a secure runtime for both JavaScript and TypeScript. As the hello world
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examples below highlight the same functionality can be created in JavaScript or
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TypeScript, and Deno will execute both.
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## JavaScript
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In this JavaScript example the message `Hello [name]` is printed to the console
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and the code ensures the name provided is capitalized.
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**Command:** `deno run hello-world.js`
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```js
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function capitalize(word) {
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return word.charAt(0).toUpperCase() + word.slice(1);
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}
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function hello(name) {
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return "Hello " + capitalize(name);
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}
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console.log(hello("john"));
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console.log(hello("Sarah"));
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console.log(hello("kai"));
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/**
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* Output:
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*
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* Hello John
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* Hello Sarah
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* Hello Kai
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**/
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```
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## TypeScript
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This TypeScript example is exactly the same as the JavaScript example above, the
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code just has the additional type information which TypeScript supports.
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The `deno run` command is exactly the same, it just references a `*.ts` file
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rather than a `*.js` file.
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**Command:** `deno run hello-world.ts`
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```ts
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function capitalize(word: string): string {
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return word.charAt(0).toUpperCase() + word.slice(1);
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}
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function hello(name: string): string {
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return "Hello " + capitalize(name);
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}
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console.log(hello("john"));
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console.log(hello("Sarah"));
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console.log(hello("kai"));
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/**
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* Output:
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*
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* Hello John
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* Hello Sarah
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* Hello Kai
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**/
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```
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