28 Sep 2022 ~ 8 min read

File Based Routing for Static Sites

In this article I will go over how to use file based routing to output as a static site multi page application.

TLDR The final source here and an online demo.

Step 1

Create a new folder called “static-site-file-based-routing” and open it up in VSCode.

mkdir static-site-file-based-routing
cd static-site-file-based-routing
code .

Step 2

Create a tsconfig.json and replace it with the following:

{
  "compilerOptions": {
    "incremental": true,
    "target": "es5",
    "module": "es2020",
    "outDir": "dist",
    "strict": true,
    "moduleResolution": "node",
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true,
    "typeRoots": [
      "node_modules/@types",
      "src/@types"
    ]
  },
  "include": [
    "src/**/*"
  ],
  "exclude": [
    "node_modules",
    "dist"
  ]
}

Step 3

Create a package.json and update it with the following:

{
  "name": "static-site-file-based-routing",
  "version": "1.0.0",
  "description": "File based routing for HTML MPA",
  "type": "module",
  "scripts": {
    "start": "wds --node-resolve --root-dir build --base-path /static-site-file-based-routing --open --watch",
    "postinstall": "npm run tsc",
    "build": "node dist/main.js --inputDir ./example --outputDir ./build",
    "dev": "node dist/main.js --inputDir ./example --outputDir ./build -w",
    "tsc": "tsc",
    "tsc:watch": "tsc -w"
  },
  "devDependencies": {
    "@pkgjs/parseargs": "^0.10.0",
    "@types/markdown-it": "^12.2.3",
    "@types/node": "^18.7.23",
    "@web/dev-server": "^0.1.34",
    "chokidar": "^3.5.3",
    "highlight.js": "^11.6.0",
    "html-format": "^1.0.2",
    "markdown-it": "^13.0.1",
    "parse5": "^7.1.1",
    "typescript": "^4.8.4"
  }
}

Then run npm install to install all the dependencies.

Note: I am using @web/dev-server to serve the site locally. You can use any server you want.

These dependencies are used for various file transformations such as markdown to HTML, HTML formatting, and file watching.

Step 4

Create a src folder and add 4 files:

src/build.ts

import * as fs from "fs";
import { compileDir, compileTarget } from "./compile.js";
import * as path from "path";
import chokidar from "chokidar";
import { publicDirectory } from "./static.js";

interface Options {
    inputDir?: string;
    outputDir?: string;
    publicDir?: string;
    watch?: boolean;
    clean?: boolean;
}

export default async function build(options: Options) {
    const inputDir = options.inputDir || "www";
    const outputDir = options.outputDir || "build";
    const publicDir = options.publicDir || "public";
    const watch = options.watch || false;
    const clean = options.clean || false;

    if (!fs.existsSync(inputDir)) {
        throw new Error(`Input directory ${inputDir} does not exist`);
    }

    if (clean) {
        if (fs.existsSync(outputDir)) {
            fs.rmdirSync(outputDir, { recursive: true });
        }
    }

    if (!fs.existsSync(outputDir)) {
        fs.mkdirSync(outputDir, { recursive: true });
    }

    if (watch) {
        console.log("Watching for changes...");
        chokidar.watch(inputDir).on("all", async (event, inputFile) => {
            console.log(event, inputFile);
            if (fs.existsSync(inputFile)) {
                const relativePath = path.relative(inputDir, inputFile);
                const outputFile = `${outputDir}/${relativePath}`;

                const stat = fs.statSync(inputFile);
                if (stat.isDirectory()) {
                    await compileDir(inputFile, outputFile);
                } else if (stat.isFile()) {
                    const filename = path.basename(inputFile);
                    if (filename === "layout.html") {
                        // Rebuild all related directories
                        const dir = path.dirname(inputFile);
                        const inDir = path.relative(inputDir, dir);
                        const outDir = `${outputDir}/${inDir}`;
                        await compileDir(dir, outDir);
                    } else {
                        await compileTarget(inputFile, outputFile);
                    }
                }
            }
        });
    } else {
        await compileDir(inputDir, outputDir);
    }

    if (publicDir.split(',').length > 1) {
        for (const dir of publicDir.split(',')) {
            publicDirectory(dir, outputDir, watch);
        }
    } else {
        publicDirectory(publicDir, outputDir, watch);
    }
}

src/compile.ts

import * as fs from "fs";
import * as path from "path";
import MarkdownIt from "markdown-it";
import hljs from "highlight.js";
import * as parse5 from "parse5";
import type { Document } from "parse5/dist/tree-adapters/default.js";
import format from 'html-format';

function compile(file: string) {
    const raw = fs.readFileSync(file, "utf-8");
    const ext = path.extname(file);

    switch (ext) {
        case ".md":
        case ".markdown":
            const md = new MarkdownIt({
                html: true,
                linkify: true,
                typographer: true,
                highlight: function (str, lang) {
                    if (lang && hljs.getLanguage(lang)) {
                        try {
                            return (
                                '<pre class="hljs"><code>' +
                                hljs.highlight(str, { language: lang, ignoreIllegals: true })
                                    .value +
                                "</code></pre>"
                            );
                        } catch (__) {
                            console.error(__);
                        }
                    }
                    return "";
                },
            });
            return parse5.parse(md.render(raw));
        case ".html":
            return parse5.parse(raw);
        default:
            break;
    }

    return raw;
}

function createHtml(options?: { head?: string; body?: string; }) {
    return `
<!DOCTYPE html>
<html lang="en">
<head>
${options?.head ?? ""}
</head>
<body>
${options?.body ?? "<slot></slot>"}
</body>
</html>
`;
}

export async function compileFile(file: string, target: string) {
    // Use regex to check if ends with index.*
    const isIndex = /index\.([a-z]+)$/i.test(file);

    if (!isIndex && !fs.statSync(file).isDirectory()) {
        // Skipping for nested layouts
        return;
    }

    const parent = path.dirname(target);

    // Render up the directory tree until we hit the root directory
    const files: string[] = [file];
    let filePath = file;
    while (filePath !== parent) {
        filePath = path.dirname(filePath);
        // Check for root level layout
        const layout = path.join(filePath, "layout.html");
        if (fs.existsSync(layout)) {
            files.unshift(layout);
        }
        if (filePath === ".") break;
    }

    // Check for root level index markdown or html
    const layout = path.join(parent, "layout.html");
    if (fs.existsSync(layout)) {
        if (
            fs.existsSync(path.join(parent, "index.html")) ||
            fs.existsSync(path.join(parent, "index.md")) ||
            fs.existsSync(path.join(parent, "index.markdown"))
        ) {
            files.unshift(layout);
        }
    }

    let output = createHtml();

    for (const item of files) {
        const doc = compile(item);
        if (typeof doc !== 'string') {
            const content = parse5.serialize(doc);
            output = mergeDocuments(output, content);
        }
    }

    // Replace extension
    const ext = path.extname(file);
    const newFile = target.replace(ext, '.html');

    // Check if parent directory exists
    const parentDir = path.dirname(newFile);
    if (!fs.existsSync(parentDir)) {
        fs.mkdirSync(parentDir, { recursive: true });
    }

    fs.writeFileSync(newFile, output);
    console.log(`--> ${newFile}`);
}

function mergeDocuments(current: string, source: string) {
    let raw = current;

    // Merge body
    const html = extractDoc(parse5.parse(source));
    // Check for <slot></slot>
    const hasSlot = raw.includes("<slot></slot>");
    if (hasSlot) {
        raw = raw.replace("<slot></slot>", parse5.serialize(html.body));
    } else {
        // Append to body
        const endBodyIdx = raw.lastIndexOf("</body>");
        const start = raw.slice(0, endBodyIdx);
        const end = raw.slice(endBodyIdx);
        const body = parse5.serialize(html.body);
        raw = start + body + end;
    }

    // Merge head
    const endHeadIdx = raw.lastIndexOf("</head>");
    const start = raw.slice(0, endHeadIdx);
    const end = raw.slice(endHeadIdx);
    const head = parse5.serialize(html.head);
    raw = start + head + end;

    // Format
    raw = format(raw);

    // Remove duplicate title tags
    const lastTitle = raw.lastIndexOf("<title>");
    const lastTitleEnd = raw.lastIndexOf("</title>");
    const title = raw.slice(lastTitle, lastTitleEnd + 8);
    raw = raw.replace(/<title>.*<\/title>/, "");
    raw = raw.replace("</head>", title + "</head>");

    return raw;
}

function extractDoc(doc: Document) {
    const html = (doc.childNodes[1] ?? doc.childNodes[0]) as unknown as Document;
    const head = html.childNodes.find(
        (node) => node.nodeName === "head"
    ) as unknown as Document;
    const body = html.childNodes.find(
        (node) => node.nodeName === "body"
    ) as unknown as Document;
    return { head, body };
}

export async function compileDir(inputDir: string, outputDir: string) {
    const files = fs.readdirSync(inputDir);
    for (const file of files) {
        const inputFile = `${inputDir}/${file}`;
        const outputFile = `${outputDir}/${file}`;

        await compileTarget(inputFile, outputFile);
    }
}

export async function compileTarget(input: string, output: string) {
    const stat = fs.statSync(input);
    if (stat.isDirectory()) {
        if (!fs.existsSync(output)) {
            fs.mkdirSync(output, { recursive: true });
        }
        await compileDir(input, output);
    } else if (stat.isFile()) {
        const ext = path.extname(input);
        if (['.html', '.md', '.markdown'].includes(ext)) {
            await compileFile(input, output);
        } else {
            const current = fs.readFileSync(input);
            const parentDir = path.dirname(output);
            if (!fs.existsSync(parentDir)) {
                fs.mkdirSync(parentDir, { recursive: true });
            }
            if (fs.existsSync(output)) {
                // Check if content is the same
                const previous = fs.readFileSync(output);
                if (Buffer.compare(current, previous) !== 0) {
                    fs.writeFileSync(output, current);
                }
            } else {
                // Copy the file
                fs.copyFileSync(input, output);
            }
        }
    }
}

src/static.ts

import * as fs from "fs";
import * as path from "path";
import chokidar from "chokidar";

export function publicDirectory(publicDir: string, outputDir: string, watch: boolean) {
    if (watch) {
        if (fs.existsSync(publicDir)) {
            chokidar.watch(publicDir).on("all", (event, inputFile) => {
                console.log(event, inputFile);
                if (fs.existsSync(inputFile)) {
                    const relativePath = path.relative(publicDir, inputFile);
                    const outputFile = `${outputDir}/${relativePath}`;

                    const stat = fs.statSync(inputFile);
                    if (stat.isDirectory()) {
                        copyStaticFiles(inputFile, outputFile);
                    } else if (stat.isFile()) {
                        fs.copyFileSync(inputFile, outputFile);
                    }
                }
            });
        }
    } else {
        // Copy static files
        if (fs.existsSync(publicDir)) {
            copyStaticFiles(publicDir, outputDir);
        }
    }
}

function copyStaticFiles(inDir: string, outDir: string) {
    const files = fs.readdirSync(inDir);
    for (const file of files) {
        const inputFile = `${inDir}/${file}`;
        const outputFile = `${outDir}/${file}`;

        const stat = fs.statSync(inputFile);
        if (stat.isDirectory()) {
            if (!fs.existsSync(outputFile)) {
                fs.mkdirSync(outputFile, { recursive: true });
            }

            copyStaticFiles(inputFile, outputFile);
        } else if (stat.isFile()) {
            fs.copyFileSync(inputFile, outputFile);
        }
    }
}

src/main.ts

#!/usr/bin/env node

// @ts-ignore
import { parseArgs } from "@pkgjs/parseargs";
import build from "./build.js";

export async function main() {
  const {
    values: { inputDir, outputDir, watch },
  } = parseArgs({
    options: {
      inputDir: {
        type: "string",
        short: "i",
      },
      outputDir: {
        type: "string",
        short: "o",
      },
      watch: {
        type: "boolean",
        short: "w",
      },
    },
    allowPositional: true,
  });

  if (inputDir === undefined || outputDir === undefined) {
    console.log("Usage: build -i <inputDir> -o <outputDir> [-w]");
    return;
  }

  await build({
    inputDir,
    outputDir,
    watch,
  });
}

main();

Step 5

Now that the project is setup we can start the typescript compiler in watch mode.

npm run ts:watch

Step 6

Now create a folder that will contain the source files for the website.

example/index.md

# Hello World

This is a test

example/style.css

body {
    background-color: #000;
    color: #fff;
}

example/layout.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Example</title>
    <link rel="stylesheet" href="style.css">
</head>
<body>
    <slot></slot>
</body>
</html>

Step 7

With the source files created we can now run the build script.

For a one time build run:

npm run build

For a watch mode run:

npm run dev

Now start the http server:

npm run start

Conclusion

As you make changes it will only update affected files and be very fast to update.

Note that this does not bundle the javascript and will be up to you if you are using node_modules in any files (for the example in the repo I show how to use UNPKG).

If you want to find the source code you can check it out here otherwise thanks for reading and let me know if you have any questions!