Builder (Legacy) | Fresh docs

Warning
The Builder class was used during the alpha phase of Fresh 2 before the Fresh vite plugin was released. You can skip this page if you’re using vite.

The Builder class is used to generate production assets of your app. You’ll typically find it being created inside your project’s dev.ts file.

dev.ts

import { Builder } from "fresh/dev";

const builder = new Builder({ target: "safari12" });

if (Deno.args.includes("build")) {
  // This creates a production build
  await builder.build();
} else {
  // This starts a development server with live reload
  await builder.listen(() => import("./main.ts"));
}

Options

You can customize the builder by passing options.

dev.ts

const builder = new Builder({
  // Browser target for generated code. Maps to https://esbuild.github.io/api/#target
  target?: string | string[];
  // The root directory of the project. All other paths will be resolved
  // against this if they're relative. (Default: `Deno.cwd()`)
  root?: string;
  // The path to your server entry point. (Default: `<root>/main.ts`)
  serverEntry?: string;
  // Where to write generated files when doing a production build.
  // (default: `<root>/_fresh/`)
  outDir?: string;
  // Path to static file directory. (Default: `<root>/static/`)
  staticDir?: string;
  // Path to island directory. (Default: `<root>/islands`)
  islandDir?: string;
  // Path to routes directory. (Default: `<root>/routes`)
  routeDir?: string;
  // File paths which should be ignored 
  ignore?: RegExp[];
  // Optionally generate production source maps
  // See https://esbuild.github.io/api/#source-maps
  sourceMap?: {
    kind?: boolean | 'linked' | 'inline' | 'external' | 'both';
    sourceRoot?: string;
    sourcesContent?: boolean;
  };
})

Registering islands

The builder is where you’ll register files that contain islands. This is the same API that Fresh uses internally.

dev.ts

const builder = new Builder();

// Path to local island
builder.registerIsland("path/to/my/Island.tsx");
// File urls work too
builder.registerIsland("file:///path/to/my/Island.tsx");
// Also islands from jsr
builder.registerIsland("jsr:@marvinh-test/fresh-island");

Adding build plugins

The Builder has a very simple processing mechanism for static files.

dev.ts

builder.onTransformStaticFile({
  pluginName: "My cool plugin",
  filter: /\.css$/,
}, (args) => {
  // Prepend `body { background: red }` to every `.css` file
  const code = `body { background: red } ${args.text}`;

  return {
    content: code,
    map: undefined, // Optional: source maps
  };
});

Info
Only static files in static/ or the value you set staticDir to will be processed. The builder won’t process anything else.

Testing

Testing applications with the Builder class involves creating a build snapshot and assigning that to each app instance.

my-app.test.ts

// Best to do this once instead of for every test case for
// performance reasons.
const builder = new Builder();
const applySnapshot = await builder.build({ snapshot: "memory" });

function testApp() {
  const app = new App()
    .get("/", () => new Response("hello"))
    .fsRoutes();

  // Applies build snapshot to this app instance.
  applySnapshot(app);
  return app;
}

Deno.test("My Test", async () => {
  const handler = testApp().handler();

  const response = await handler(new Request("http://localhost"));
  const text = await response.text();

  if (text !== "hello") {
    throw new Error("fail");
  }
});

Tailwindcss is a utility-first CSS framework that generates CSS out of the class names that are used in JSX. Since we use Tailwindcss ourselves here at Deno, Fresh ships with an official plugin for that.

Usage

Set nodeModulesDir in deno.json to "auto" or "manual"

deno.json

  {
    "name": "@example/my-cool-project"
+   "nodeModulesDir": "auto",
    "imports": {
      ...
    }
  }

Run deno install jsr:@fresh/plugin-tailwind
Update dev.ts:

dev.ts

  import { Builder } from "fresh/dev";
+ import { tailwind } from "@fresh/plugin-tailwind";
  
  const builder = new Builder();
+ tailwind(builder);

Add @import "tailwindcss"; at the top of your main stylesheet.

For more information on how to use tailwindcss, check out their documentation.

Options

You can customize the tailwind plugin via the following options:

dev.ts

tailwind(builder, app, {
  // Exclude certain files from processing
  exclude: ["/admin/**", "*.temp.css"],
  // Force optimization (defaults to production mode)
  optimize: true,
  // Exclude base styles
  base: null,
});

Tailwindcss v3

If can’t update to the current version of tailwindcss we have a dedicated @fresh/plugin-tailwindcss-v3 plugin that uses tailwindcss v3. That way you can decided on your own when it’s best to update to v4.

dev.ts

import { Builder } from "fresh/dev";
import { tailwind } from "@fresh/plugin-tailwind-v3";

tailwind(builder, {});