Javascript modules: Difference between revisions

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In recent years, javascript has been extended to support modules.
In recent years, javascript has been extended to support modules with import semantics.


= Documentation =
= Documentation =
Line 40: Line 40:
== Imports ==
== Imports ==
<blockquote>
<blockquote>
<syntaxhighlight lang="javacript">
<syntaxhighlight lang="javascript">
import * as Foo from './modules/foo.js'          // exported symbols accessed on 'Foo' namespace
import * as Foo from './modules/foo.js'          // exported symbols accessed on 'Foo' namespace
import { Bar, Baz } from './modules/foo.js'      // import exported 'Bar', 'Baz' into current namespace
import { Bar, Baz } from './modules/foo.js'      // import exported 'Bar', 'Baz' into current namespace
Line 50: Line 50:
<blockquote>
<blockquote>
<syntaxhighlight lang="javascript">
<syntaxhighlight lang="javascript">
// symbols can be exported in one location
export { foo, bar, baz };
export { foo, bar, baz };
export * from 'foo.js'
 
export { name } from 'foo.js'
// symbols can be exported at declaration. ex:
export function foo() { ... };
export const number = 123;
</syntaxhighlight>
</syntaxhighlight>
</blockquote><!-- Exports -->
</blockquote><!-- Syntax -->
= Exporting Symbols =
<blockquote>


== Exporting Default ==
You can also export one function as default
<blockquote>
<syntaxhighlight lang="javascript">
<syntaxhighlight lang="javascript">
// ${project}/modules/math.js
// math.js
 
export default function sum(a, b) {
export default function sum(a, b) {
     return a + b;
     return a + b;
}
}
</syntaxhighlight>


<syntaxhighlight lang="javascript">
// main.js
import * as Math from './modules/math.js'
import * as Math from './math.js'
 
Math.default(2, 2); // ('default' is the 'sum' function)
Math.default(1, 1) // -> 2  ('default' is the 'sum' function)
</syntaxhighlight>
</syntaxhighlight>
</blockquote><!-- Exporting Default -->
</blockquote><!-- Exports -->
</blockquote><!-- Exporting Symbols -->
</blockquote><!-- Syntax -->

Latest revision as of 16:03, 18 December 2022

In recent years, javascript has been extended to support modules with import semantics.

Documentation

MDN modules https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules

Example

<!-- index.html -->
<html lang="en">
  <head>
    <script type="module" src="main.js"></script>   <!-- add main.js to file -->
  </head>
</html>
// main.js
import * as Math from './modules/math.js'

console.log(Math.sum(1, 2));
// modules/math.js
export function sum(a, b) {
    return a + b;
}

Syntax

Imports

import * as Foo from './modules/foo.js'          // exported symbols accessed on 'Foo' namespace
import { Bar, Baz } from './modules/foo.js'      // import exported 'Bar', 'Baz' into current namespace
import { Bar as barbar } from './modules/foo.js' // import exported 'Bar' as symbol 'barbar' within current namespace

Exports

// symbols can be exported in one location
export { foo, bar, baz };

// symbols can be exported at declaration. ex:
export function foo() { ... };
export const number = 123;

You can also export one function as default

// math.js
export default function sum(a, b) {
    return a + b;
}

// main.js
import * as Math from './math.js'
Math.default(2, 2); // ('default' is the 'sum' function)