hugo/content/en/_common/functions/js/options.md

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params

(map or slice) Params that can be imported as JSON in your JS files, e.g.

{{ $js := resources.Get "js/main.js" | js.Build (dict "params" (dict "api" "https://example.org/api")) }}

And then in your JS file:

import * as params from '@params';

Note that this is meant for small data sets, e.g., configuration settings. For larger data sets, please put/mount the files into assets and import them directly.

minify

(bool) Whether to minify the generated JS code. Default is false.

loaders

{{< new-in 0.140.0 />}}

(map) Configuring a loader for a given file type lets you load that file type with an import statement or a require call. For example, configuring the .png file extension to use the data URL loader means importing a .png file gives you a data URL containing the contents of that image. Loaders available are none, base64, binary, copy, css, dataurl, default, empty, file, global-css, js, json, jsx, local-css, text, ts, tsx. See https://esbuild.github.io/api/#loader.

inject

(slice) This option allows you to automatically replace a global variable with an import from another file. The path names must be relative to assets. See https://esbuild.github.io/api/#inject.

shims

(map) This option allows swapping out a component with another. A common use case is to load dependencies like React from a CDN (with shims) when in production, but running with the full bundled node_modules dependency during development:

{{ $shims := dict "react" "js/shims/react.js"  "react-dom" "js/shims/react-dom.js" }}
{{ $js = $js | js.Build dict "shims" $shims }}

The shim files may look like these:

// js/shims/react.js
module.exports = window.React;

// js/shims/react-dom.js
module.exports = window.ReactDOM;

With the above, these imports should work in both scenarios:

import * as React from 'react';
import * as ReactDOM from 'react-dom/client';

target

(string) The language target. One of: es5, es2015, es2016, es2017, es2018, es2019, es2020, es2021, es2022, es2023, es2024, or esnext. Default is esnext.

platform

{{< new-in 0.140.0 />}}

(string) One of browser, node, neutral. Default is browser. See https://esbuild.github.io/api/#platform.

externals

(slice) External dependencies. Use this to trim dependencies you know will never be executed. See https://esbuild.github.io/api/#external.

defines

(map) This option allows you to define a set of string replacements to be performed when building. It must be a map where each key will be replaced by its value.

{{ $defines := dict "process.env.NODE_ENV" `"development"` }}

drop

{{< new-in 0.144.0 />}}

(string) Edit your source code before building to drop certain constructs: One of debugger or console.

See https://esbuild.github.io/api/#drop

sourceMap

(string) The type of source map to generate. One of external, inline, linked, or none. Default is none. Linked and external source maps will be written to the target with the output file name + ".map". When linked a sourceMappingURL will also be written to the output file.

sourcesContent

{{< new-in 0.140.0 />}}

(bool) Whether to include the content of the source files in the source map. Default is true.

JSX

(string) How to handle/transform JSX syntax. One of: transform, preserve, automatic. Default is transform. Notably, the automatic transform was introduced in React 17+ and will cause the necessary JSX helper functions to be imported automatically. See https://esbuild.github.io/api/#jsx.

JSXImportSource

(string) Which library to use to automatically import its JSX helper functions from. This only works if JSX is set to automatic. The specified library needs to be installed through npm and expose certain exports. See https://esbuild.github.io/api/#jsx-import-source.

The combination of JSX and JSXImportSource is helpful if you want to use a non-React JSX library like Preact, e.g.:

{{ $js := resources.Get "js/main.jsx" | js.Build (dict "JSX" "automatic" "JSXImportSource" "preact") }}

With the above, you can use Preact components and JSX without having to manually import h and Fragment every time:

import { render } from 'preact';

const App = () => <>Hello world!</>;

const container = document.getElementById('app');
if (container) render(<App />, container);