Prettier support for .astro files (#106)

* docs: fix readme

* chore: scaffold prettier plugin

* chore(prettier): switch to cjs

* test(prettier): scaffold prettier tests

* test(prettier): add simple prettier tests

* feat(prettier): first pass

* refactor: expose parser as CJS export

* test(prettier): add long expression

* refactor(prettier): use Astro parser + built-in prettier doc for prettier plugin

* chore: remove parser from git

* chore: add prettier-plugin-astro `build` to workflow

* chore: update package-lock

* chore: do not build prettier-plugin-astro

* fix: update engines

* chore: remove NPM restriction

* chore: fix workflow paths

* chore: update build script

* test: fix prettier expr test

* chore: fix parser build on windows

* refactor: add parser tsconfig, extending base config

* chore: relax ban-ts-comment

* chore: fix lint issue

Co-authored-by: Nate Moore <nate@skypack.dev>

.eslintrc.cjs

@@ -3,7 +3,7 @@ module.exports = {
   extends: ['plugin:@typescript-eslint/recommended', 'prettier'],
   plugins: ['@typescript-eslint', 'prettier'],
   rules: {
-    '@typescript-eslint/ban-ts-comment': 'warn',
+    '@typescript-eslint/ban-ts-comment': 'off',
     '@typescript-eslint/camelcase': 'off',
     '@typescript-eslint/explicit-module-boundary-types': 'off',
     '@typescript-eslint/no-empty-function': 'off',

.github/workflows/nodejs.yml

@@ -25,7 +25,10 @@ jobs:
           npm ci
           npm run build
 
-          cd examples/kitchen-sink
+          cd prettier-plugin-astro
+          npm ci
+          
+          cd ../examples/kitchen-sink
           npm ci
           npm run build
           cd ../..

.gitignore

@@ -1,5 +1,6 @@
 node_modules/
 lib/
+parser/
 dist/
 *.tsbuildinfo
 .DS_Store

examples/snowpack/package-lock.json

@@ -1900,9 +1900,9 @@
           "integrity": "sha512-xFbRxM1tahm08yHBP16MMjVUAvDaBMD38zsM9EMAUN61omwLmKlOpB/Zku5QkjZ8TZ4vn53pj+t518cH0S03RQ=="
         },
         "balanced-match": {
-          "version": "1.0.0",
-          "resolved": "https://registry.npmjs.org/balanced-match/-/balanced-match-1.0.0.tgz",
-          "integrity": "sha1-ibTRmasr7kneFk6gK4nORi1xt2c="
+          "version": "1.0.2",
+          "resolved": "https://registry.npmjs.org/balanced-match/-/balanced-match-1.0.2.tgz",
+          "integrity": "sha512-3oSeUO0TMV67hN1AmbXsK4yaqU7tjiHlbxRDZOpH0KW9+CeX4bRAaX0Anxt0tx2MrpRpWwQaPwIlISEJhYU5Pw=="
         },
         "bcrypt-pbkdf": {
           "version": "1.0.2",
@@ -4850,9 +4850,9 @@
           "integrity": "sha512-iVICrxOzCynf/SNaBQCw34eM9jROU/s5rzIhpOvzhzuYHfJR/DhZfDkXiZSgKXfgv26HT3Yni3AV/DGw0cGnnw=="
         },
         "snowpack": {
-          "version": "3.3.1",
-          "resolved": "https://registry.npmjs.org/snowpack/-/snowpack-3.3.1.tgz",
-          "integrity": "sha512-93utJcqKkvQ9StnliIKqDp02laf+7MnPVULacuvNEVg8nHdmON0jKVuG5ezGAMtFRUGBfeQ+kO417tifG1lQUw==",
+          "version": "3.3.4",
+          "resolved": "https://registry.npmjs.org/snowpack/-/snowpack-3.3.4.tgz",
+          "integrity": "sha512-Yj4WlVwLHH9LRb0MwTklIWPtE4L20RMFDpuWr75kS6wvHtIJWUf0/rma8PcoLMKYtSJirsDmrglI9rceFIx+Zg==",
           "requires": {
             "cli-spinners": "^2.5.0",
             "default-browser-id": "^2.0.0",
@@ -4890,9 +4890,9 @@
           }
         },
         "socks": {
-          "version": "2.6.0",
-          "resolved": "https://registry.npmjs.org/socks/-/socks-2.6.0.tgz",
-          "integrity": "sha512-mNmr9owlinMplev0Wd7UHFlqI4ofnBnNzFuzrm63PPaHgbkqCFe4T5LzwKmtQ/f2tX0NTpcdVLyD/FHxFBstYw==",
+          "version": "2.6.1",
+          "resolved": "https://registry.npmjs.org/socks/-/socks-2.6.1.tgz",
+          "integrity": "sha512-kLQ9N5ucj8uIcxrDwjm0Jsqk06xdpBjGNQtpXy4Q8/QY2k+fY7nZH8CARy+hkbG+SGAovmzzuauCpBlb8FrnBA==",
           "requires": {
             "ip": "^1.1.5",
             "smart-buffer": "^4.1.0"

package.json

@@ -7,6 +7,7 @@
   "exports": {
     ".": "./astro.mjs",
     "./snowpack-plugin": "./snowpack-plugin.cjs",
+    "./parser": "./parser.cjs",
     "./components/*.astro": "./components/*.astro"
   },
   "bin": {
@@ -20,7 +21,10 @@
     "astro.mjs"
   ],
   "scripts": {
-    "build": "tsc",
+    "build": "npm run build:core && npm run build:parser",
+    "build:core": "tsc -p tsconfig.json",
+    "build:parser": "tsc -p tsconfig.parser.json",
+    "postbuild:parser": "echo '{ \"type\": \"commonjs\" }' > parser/package.json",
     "dev": "tsc --watch",
     "lint": "eslint 'src/**/*.{js,ts}'",
     "format": "prettier -w '{src,test}/**/*.{js,ts}'",
@@ -99,7 +103,7 @@
     "uvu": "^0.5.1"
   },
   "engines": {
-    "node": "~14.0.0",
-    "npm": ">=6.14.0 <7.0.0"
+    "node": ">=14.0.0",
+    "npm": ">=6.14.0"
   }
 }

parser.cjs

@@ -0,0 +1 @@
+module.exports = require('./parser/index.js');

prettier-plugin-astro/index.js

@@ -0,0 +1,154 @@
+const {
+  doc: {
+    builders: { concat, hardline },
+  },
+} = require('prettier');
+const { parse } = require('astro/parser');
+
+/** @type {Partial<import('prettier').SupportLanguage>[]} */
+module.exports.languages = [
+  {
+    name: 'astro',
+    parsers: ['astro'],
+    extensions: ['.astro'],
+    vscodeLanguageIds: ['astro'],
+  },
+];
+
+/** @type {Record<string, import('prettier').Parser>} */
+module.exports.parsers = {
+  astro: {
+    parse: (text) => {
+      let { html, css, module: frontmatter } = parse(text);
+      html = html ? { ...html, text: text.slice(html.start, html.end), isRoot: true } : null;
+      return [frontmatter, html, css].filter((v) => v);
+    },
+    locStart(node) {
+      return node.start;
+    },
+    locEnd(node) {
+      return node.end;
+    },
+    astFormat: 'astro-ast',
+  },
+  'astro-expression': {
+    parse: (text, parsers) => {
+      return { text };
+    },
+    locStart(node) {
+      return node.start;
+    },
+    locEnd(node) {
+      return node.end;
+    },
+    astFormat: 'astro-expression',
+  }
+};
+
+const findExpressionsInAST = (node, collect = []) => {
+  if (node.type === 'MustacheTag') {
+    return collect.concat(node);
+  }
+  if (node.children) {
+    collect.push(...[].concat(...node.children.map(child => findExpressionsInAST(child))));
+  }
+  return collect;
+}
+
+const formatExpression = ({ expression: { codeStart, codeEnd, children }}, text, options) => {
+  if (children.length === 0) {
+    if ([`'`, `"`].includes(codeStart[0])) {
+      return `<script $ lang="ts">${codeStart}${codeEnd}</script>`
+    }
+    return `{${codeStart}${codeEnd}}`;
+  }
+
+  return `<script $ lang="ts">${text}</script>`;
+}
+
+const isAstroScript = (node) => node.type === 'concat' && node.parts[0] === '<script' && node.parts[1].type === 'indent' && node.parts[1].contents.parts.find(v => v === '$');
+
+const walkDoc = (doc) => {
+  let inAstroScript = false;
+  const recurse = (node, { parent }) => {
+    if (node.type === 'concat') {
+      if (isAstroScript(node)) {
+        inAstroScript = true;
+        parent.contents = { type: 'concat', parts: ['{'] };
+      }
+      return node.parts.map(part => recurse(part, { parent: node }));
+    }
+    if (inAstroScript) {
+      if (node.type === 'break-parent') {
+        parent.parts = parent.parts.filter(part => !['break-parent', 'line'].includes(part.type));
+      }
+      if (node.type === 'indent') {
+        parent.parts = parent.parts.map(part => {
+          if (part.type !== 'indent') return part;
+          return {
+            type: 'concat',
+            parts: [part.contents]
+          }
+        })
+      }
+      if (typeof node === 'string' && node.endsWith(';')) {
+        parent.parts = parent.parts.map(part => {
+          if (typeof part === 'string' && part.endsWith(';')) return part.slice(0, -1);
+          return part;
+        });
+      }
+      if (node === '</script>') {
+        parent.parts = parent.parts.map(part => part === '</script>' ? '}' : part);
+        inAstroScript = false;
+      }
+    }
+    if (['group', 'indent'].includes(node.type)) {
+      return recurse(node.contents, { parent: node });
+    }
+  }
+  recurse(doc, { parent: null });
+}
+
+/** @type {Record<string, import('prettier').Printer>} */
+module.exports.printers = {
+  'astro-ast': {
+    print(path, opts, print) {
+      const node = path.getValue();
+
+      if (Array.isArray(node)) return concat(path.map(print));
+      if (node.type === 'Fragment') return concat(path.map(print, 'children'));
+
+      return node;
+    },
+    embed(path, print, textToDoc, options) {
+      const node = path.getValue();
+      if (node.type === 'Script' && node.context === 'setup') {
+        return concat(['---', hardline, textToDoc(node.content, { ...options, parser: 'typescript' }), '---', hardline, hardline]);
+      }
+      if (node.type === 'Fragment' && node.isRoot) {
+        const expressions = findExpressionsInAST(node);
+        if (expressions.length > 0) {
+          const parts = [].concat(...expressions.map((expr, i, all) => {
+            const prev = all[i - 1];
+            const start = node.text.slice((prev?.end ?? node.start) - node.start, expr.start - node.start);
+            const exprText = formatExpression(expr, node.text.slice(expr.start - node.start + 1, expr.end - node.start - 1), options);
+
+            if (i === all.length - 1) {
+              const end = node.text.slice(expr.end - node.start);
+              return [start, exprText, end]
+            }
+
+            return [start, exprText]
+          }));
+          const html = parts.join('\n');
+          const doc = textToDoc(html, { parser: 'html' });
+          walkDoc(doc);
+          return doc;
+        }
+        return textToDoc(node.text, { parser: 'html' });
+      }
+
+      return null;
+    },
+  },
+};

prettier-plugin-astro/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "prettier-plugin-astro",
+  "version": "0.0.1",
+  "main": "index.js",
+  "type": "commonjs",
+  "private": true,
+  "devDependencies": {
+    "prettier": "^2.2.1"
+  },
+  "dependencies": {
+    "astro": "file:.."
+  }
+}

src/runtime.ts

@@ -229,13 +229,13 @@ interface RuntimeOptions {
   logging: LogOptions;
 }
 
-/** Create a new Snowpack instance to power Astro */
 interface CreateSnowpackOptions {
   env: Record<string, any>;
   mode: RuntimeMode;
   resolvePackageUrl?: (pkgName: string) => Promise<string>;
 }
 
+/** Create a new Snowpack instance to power Astro */
 async function createSnowpack(astroConfig: AstroConfig, options: CreateSnowpackOptions) {
   const { projectRoot, astroRoot, extensions } = astroConfig;
   const { env, mode, resolvePackageUrl } = options;

test/astro-prettier.test.js

@@ -0,0 +1,44 @@
+import { suite } from 'uvu';
+import * as assert from 'uvu/assert';
+import { format } from './test-utils.js';
+import { setup } from './helpers.js';
+
+const Prettier = suite('Prettier formatting');
+
+setup(Prettier, './fixtures/astro-prettier');
+
+/** 
+  * Utility to get `[src, out]` files 
+  * @param name {string}
+  * @param ctx {any}
+  */
+const getFiles = async (name, { readFile }) => {
+  const [src, out] = await Promise.all([readFile(`/in/${name}.astro`), readFile(`/out/${name}.astro`)]);
+  return [src, out];
+}
+
+Prettier('can format a basic Astro file', async (ctx) => {
+  const [src, out] = await getFiles('basic', ctx);
+  assert.not.equal(src, out);
+
+  const formatted = format(src);
+  assert.equal(formatted, out);
+});
+
+Prettier('can format an Astro file with frontmatter', async (ctx) => {
+  const [src, out] = await getFiles('frontmatter', ctx);
+  assert.not.equal(src, out);
+  
+  const formatted = format(src);
+  assert.equal(formatted, out);
+});
+
+Prettier('can format an Astro file with embedded JSX expressions', async (ctx) => {
+  const [src, out] = await getFiles('embedded-expr', ctx);
+  assert.not.equal(src, out);
+  
+  const formatted = format(src);
+  assert.equal(formatted, out);
+});
+
+Prettier.run();

test/fixtures/astro-prettier/in/basic.astro

@@ -0,0 +1,13 @@
+<!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>Document</title>
+</head>
+        <body>
+          <h1>
+            Hello world!</h1>
+        </body>
+</html>

test/fixtures/astro-prettier/in/embedded-expr.astro

@@ -0,0 +1,26 @@
+---
+      import Color from '../components/Color.jsx';
+
+  let title = 
+    'My Site';
+
+      const colors = ['red', 'yellow', 'blue',];
+---
+
+
+
+
+
+<html lang="en">
+          <head>
+            <title>My site</title>
+          </head>
+          <body>
+            <h1>{title}</h1>
+
+              {"I'm some super long text and oh boy I sure do hope this formatter doesn't break me!"}
+
+            {colors.map(color => (
+              <div><Color name={color} /></div>))}
+          </body>
+</html>

test/fixtures/astro-prettier/in/frontmatter.astro

@@ -0,0 +1,18 @@
+---
+      import Color from '../components/Color.jsx';
+
+  let title = 
+    'My Site';
+
+      const colors = ['red', 'yellow', 'blue',];
+---
+
+
+<html lang="en">
+          <head>
+            <title>My site</title>
+          </head>
+          <body>
+            <h1>{title}</h1>
+          </body>
+</html>

test/fixtures/astro-prettier/out/basic.astro

@@ -0,0 +1,12 @@
+<!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>Document</title>
+  </head>
+  <body>
+    <h1>Hello world!</h1>
+  </body>
+</html>

test/fixtures/astro-prettier/out/embedded-expr.astro

@@ -0,0 +1,24 @@
+---
+import Color from "../components/Color.jsx";
+
+let title = "My Site";
+
+const colors = ["red", "yellow", "blue"];
+---
+
+<html lang="en">
+  <head>
+    <title>My site</title>
+  </head>
+  <body>
+    <h1>{title}</h1>
+
+    {"I'm some super long text and oh boy I sure do hope this formatter doesn't break me!"}
+
+    {colors.map((color) => (
+      <div>
+        <Color name={color} />
+      </div>
+    ))}
+  </body>
+</html>

test/fixtures/astro-prettier/out/frontmatter.astro

@@ -0,0 +1,16 @@
+---
+import Color from "../components/Color.jsx";
+
+let title = "My Site";
+
+const colors = ["red", "yellow", "blue"];
+---
+
+<html lang="en">
+  <head>
+    <title>My site</title>
+  </head>
+  <body>
+    <h1>{title}</h1>
+  </body>
+</html>

test/helpers.js

@@ -1,7 +1,8 @@
 import { fileURLToPath } from 'url';
 import { build as astroBuild } from '../lib/build.js';
-import { loadConfig } from '../lib/config.js';
+import { readFile } from 'fs/promises';
 import { createRuntime } from '../lib/runtime.js';
+import { loadConfig } from '../lib/config.js';
 import * as assert from 'uvu/assert';
 /** setup fixtures for tests */
 export function setup(Suite, fixturePath) {
@@ -23,6 +24,10 @@ export function setup(Suite, fixturePath) {
     }
 
     context.runtime = runtime;
+    context.readFile = async (path) => {
+      const resolved = fileURLToPath(new URL(`${fixturePath}${path}`, import.meta.url));
+      return readFile(resolved).then(r => r.toString('utf-8'));
+    }
   });
 
   Suite.after(async () => {

test/test-utils.js

@@ -1,5 +1,18 @@
 import cheerio from 'cheerio';
+import prettier from 'prettier';
+import { fileURLToPath } from 'url';
 /** load html */
 export function doc(html) {
   return cheerio.load(html);
 }
+
+/** 
+  * format the contents of an astro file 
+  * @param contents {string}
+  */
+export function format(contents) {
+  return prettier.format(contents, {
+      parser: 'astro',
+      plugins: [fileURLToPath(new URL('../prettier-plugin-astro', import.meta.url))]
+  })
+}

tsconfig.base.json

@@ -0,0 +1,10 @@
+{
+  "compilerOptions": {
+    "declaration": true,
+    "strict": true,
+    "moduleResolution": "node",
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true
+  }
+}

tsconfig.json

@@ -1,72 +1,9 @@
 {
+  "extends": "./tsconfig.base.json",
   "include": ["src"],
   "compilerOptions": {
-    /* Visit https://aka.ms/tsconfig.json to read more about this file */
-
-    /* Basic Options */
-    // "incremental": true,                         /* Enable incremental compilation */
-    "target": "ES2020",                             /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019', 'ES2020', or 'ESNEXT'. */
-    "module": "ES2020",                             /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', 'es2020', or 'ESNext'. */
-    // "lib": [],                                   /* Specify library files to be included in the compilation. */
-    // "allowJs": true,                             /* Allow javascript files to be compiled. */
-    // "checkJs": true,                             /* Report errors in .js files. */
-    // "jsx": "preserve",                           /* Specify JSX code generation: 'preserve', 'react-native', 'react', 'react-jsx' or 'react-jsxdev'. */
-    "declaration": true,                            /* Generates corresponding '.d.ts' file. */
-    // "declarationMap": true,                      /* Generates a sourcemap for each corresponding '.d.ts' file. */
-    // "sourceMap": true,                           /* Generates corresponding '.map' file. */
-    // "outFile": "./",                             /* Concatenate and emit output to single file. */
-    "outDir": "./lib",                              /* Redirect output structure to the directory. */
-    // "rootDir": "./",                             /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
-    // "composite": true,                           /* Enable project compilation */
-    // "tsBuildInfoFile": "./",                     /* Specify file to store incremental compilation information */
-    // "removeComments": true,                      /* Do not emit comments to output. */
-    // "noEmit": true,                              /* Do not emit outputs. */
-    // "importHelpers": true,                       /* Import emit helpers from 'tslib'. */
-    // "downlevelIteration": true,                  /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
-    // "isolatedModules": true,                     /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */
-
-    /* Strict Type-Checking Options */
-    "strict": true,                                 /* Enable all strict type-checking options. */
-    // "noImplicitAny": true,                       /* Raise error on expressions and declarations with an implied 'any' type. */
-    // "strictNullChecks": true,                    /* Enable strict null checks. */
-    // "strictFunctionTypes": true,                 /* Enable strict checking of function types. */
-    // "strictBindCallApply": true,                 /* Enable strict 'bind', 'call', and 'apply' methods on functions. */
-    // "strictPropertyInitialization": true,        /* Enable strict checking of property initialization in classes. */
-    // "noImplicitThis": true,                      /* Raise error on 'this' expressions with an implied 'any' type. */
-    // "alwaysStrict": true,                        /* Parse in strict mode and emit "use strict" for each source file. */
-
-    /* Additional Checks */
-    // "noUnusedLocals": true,                      /* Report errors on unused locals. */
-    // "noUnusedParameters": true,                  /* Report errors on unused parameters. */
-    // "noImplicitReturns": true,                   /* Report error when not all code paths in function return a value. */
-    // "noFallthroughCasesInSwitch": true,          /* Report errors for fallthrough cases in switch statement. */
-    // "noUncheckedIndexedAccess": true,            /* Include 'undefined' in index signature results */
-    // "noPropertyAccessFromIndexSignature": true,  /* Require undeclared properties from index signatures to use element accesses. */
-
-    /* Module Resolution Options */
-    "moduleResolution": "node",                     /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
-    // "baseUrl": "./",                             /* Base directory to resolve non-absolute module names. */
-    // "paths": {},                                 /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
-    // "rootDirs": [],                              /* List of root folders whose combined content represents the structure of the project at runtime. */
-    // "typeRoots": [],                             /* List of folders to include type definitions from. */
-    // "types": [],                                 /* Type declaration files to be included in compilation. */
-    // "allowSyntheticDefaultImports": true,        /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
-    "esModuleInterop": true,                        /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
-    // "preserveSymlinks": true,                    /* Do not resolve the real path of symlinks. */
-    // "allowUmdGlobalAccess": true,                /* Allow accessing UMD globals from modules. */
-
-    /* Source Map Options */
-    // "sourceRoot": "",                            /* Specify the location where debugger should locate TypeScript files instead of source locations. */
-    // "mapRoot": "",                               /* Specify the location where debugger should locate map files instead of generated locations. */
-    // "inlineSourceMap": true,                     /* Emit a single file with source maps instead of having a separate file. */
-    // "inlineSources": true,                       /* Emit the source alongside the sourcemaps within a single file; requires '--inlineSourceMap' or '--sourceMap' to be set. */
-
-    /* Experimental Options */
-    // "experimentalDecorators": true,              /* Enables experimental support for ES7 decorators. */
-    // "emitDecoratorMetadata": true,               /* Enables experimental support for emitting type metadata for decorators. */
-
-    /* Advanced Options */
-    "skipLibCheck": true,                           /* Skip type checking of declaration files. */
-    "forceConsistentCasingInFileNames": true        /* Disallow inconsistently-cased references to the same file. */
+    "target": "ES2020",
+    "module": "ES2020",
+    "outDir": "./lib"
   }
 }

tsconfig.parser.json

@@ -0,0 +1,9 @@
+{
+  "extends": "./tsconfig.base.json",
+  "include": ["src/parser"],
+  "compilerOptions": {
+    "target": "ES2020",
+    "module": "CommonJS",
+    "outDir": "./parser"
+  }
+}