[labs/analyzer] Add support for analyzing function declarations (#3655)

* Add support for analyzing function declarations

* Add manifest emit for FunctionDeclaration

* Fix typo

* Remove unused export

.changeset/nice-rockets-smile.md

@@ -0,0 +1,5 @@
+---
+'@lit-labs/analyzer': minor
+---
+
+Added support for analyzing function declarations.

packages/labs/analyzer/src/index.ts

@@ -26,6 +26,7 @@ export type {
   PackageJson,
   ModuleWithLitElementDeclarations,
   DeprecatableDescribed,
+  FunctionDeclaration,
 } from './lib/model.js';
 
 export type {AbsolutePath, PackagePath} from './lib/paths.js';

packages/labs/analyzer/src/lib/javascript/functions.ts

@@ -12,9 +12,58 @@
 
 import ts from 'typescript';
 import {DiagnosticsError} from '../errors.js';
-import {AnalyzerInterface, Parameter, Return} from '../model.js';
+import {
+  AnalyzerInterface,
+  DeclarationInfo,
+  FunctionDeclaration,
+  Parameter,
+  Return,
+} from '../model.js';
 import {getTypeForNode, getTypeForType} from '../types.js';
-import {parseJSDocDescription} from './jsdoc.js';
+import {parseJSDocDescription, parseNodeJSDocInfo} from './jsdoc.js';
+import {hasDefaultModifier, hasExportModifier} from '../utils.js';
+
+/**
+ * Returns the name of a function declaration.
+ */
+const getFunctionDeclarationName = (declaration: ts.FunctionDeclaration) => {
+  const name =
+    declaration.name?.text ??
+    // The only time a function declaration will not have a name is when it is
+    // a default export, aka `export default function() {...}`
+    (hasDefaultModifier(declaration) ? 'default' : undefined);
+  if (name === undefined) {
+    throw new DiagnosticsError(
+      declaration,
+      'Unexpected function declaration without a name'
+    );
+  }
+  return name;
+};
+
+export const getFunctionDeclarationInfo = (
+  declaration: ts.FunctionDeclaration,
+  analyzer: AnalyzerInterface
+): DeclarationInfo => {
+  const name = getFunctionDeclarationName(declaration);
+  return {
+    name,
+    factory: () => getFunctionDeclaration(declaration, name, analyzer),
+    isExport: hasExportModifier(declaration),
+  };
+};
+
+const getFunctionDeclaration = (
+  declaration: ts.FunctionLikeDeclaration,
+  name: string,
+  analyzer: AnalyzerInterface
+): FunctionDeclaration => {
+  return new FunctionDeclaration({
+    name,
+    ...parseNodeJSDocInfo(declaration),
+    ...getFunctionLikeInfo(declaration, analyzer),
+  });
+};
 
 /**
  * Returns information on FunctionLike nodes

packages/labs/analyzer/src/lib/javascript/modules.ts

@@ -37,6 +37,7 @@ import {
   getSpecifierString,
 } from '../references.js';
 import {parseModuleJSDocInfo} from './jsdoc.js';
+import {getFunctionDeclarationInfo} from './functions.js';
 
 /**
  * Returns the sourcePath, jsPath, and package.json contents of the containing
@@ -116,6 +117,8 @@ export const getModule = (
   for (const statement of sourceFile.statements) {
     if (ts.isClassDeclaration(statement)) {
       addDeclaration(getClassDeclarationInfo(statement, analyzer));
+    } else if (ts.isFunctionDeclaration(statement)) {
+      addDeclaration(getFunctionDeclarationInfo(statement, analyzer));
     } else if (ts.isVariableStatement(statement)) {
       getVariableDeclarationInfo(statement, analyzer).forEach(addDeclaration);
     } else if (ts.isEnumDeclaration(statement)) {

packages/labs/analyzer/src/lib/model.ts

@@ -355,21 +355,17 @@ export interface ClassMethodInit extends FunctionLikeInit {
   source?: SourceReference | undefined;
 }
 
-export class ClassMethod extends Declaration {
+export class ClassMethod extends FunctionDeclaration {
   static?: boolean | undefined;
   privacy?: Privacy | undefined;
   inheritedFrom?: Reference | undefined;
   source?: SourceReference | undefined;
-  parameters?: Parameter[] | undefined;
-  return?: Return | undefined;
   constructor(init: ClassMethodInit) {
     super(init);
     this.static = init.static;
     this.privacy = init.privacy;
     this.inheritedFrom = init.inheritedFrom;
     this.source = init.source;
-    this.parameters = init.parameters;
-    this.return = init.return;
   }
 }
 

packages/labs/analyzer/src/test/javascript/functions_test.ts

@@ -0,0 +1,115 @@
+/**
+ * @license
+ * Copyright 2022 Google LLC
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+import {suite} from 'uvu';
+// eslint-disable-next-line import/extensions
+import * as assert from 'uvu/assert';
+import {fileURLToPath} from 'url';
+import {getSourceFilename, languages} from '../utils.js';
+
+import {
+  createPackageAnalyzer,
+  Analyzer,
+  AbsolutePath,
+  Module,
+} from '../../index.js';
+
+for (const lang of languages) {
+  const test = suite<{
+    analyzer: Analyzer;
+    packagePath: AbsolutePath;
+    module: Module;
+  }>(`Module tests (${lang})`);
+
+  test.before((ctx) => {
+    try {
+      const packagePath = fileURLToPath(
+        new URL(`../../test-files/${lang}/functions`, import.meta.url).href
+      ) as AbsolutePath;
+      const analyzer = createPackageAnalyzer(packagePath);
+
+      const result = analyzer.getPackage();
+      const file = getSourceFilename('functions', lang);
+      const module = result.modules.find((m) => m.sourcePath === file);
+      if (module === undefined) {
+        throw new Error(`Analyzer did not analyze file '${file}'`);
+      }
+
+      ctx.packagePath = packagePath;
+      ctx.analyzer = analyzer;
+      ctx.module = module;
+    } catch (error) {
+      // Uvu has a bug where it silently ignores failures in before and after,
+      // see https://github.com/lukeed/uvu/issues/191.
+      console.error('uvu before error', error);
+      process.exit(1);
+    }
+  });
+
+  test('Function 1', ({module}) => {
+    const exportedFn = module.getResolvedExport('function1');
+    const fn = module.getDeclaration('function1');
+    assert.equal(fn, exportedFn);
+    assert.ok(fn?.isFunctionDeclaration());
+    assert.equal(fn.name, `function1`);
+    assert.equal(fn.description, `Function 1 description`);
+    assert.equal(fn.summary, undefined);
+    assert.equal(fn.parameters?.length, 0);
+    assert.equal(fn.deprecated, undefined);
+  });
+
+  test('Function 2', ({module}) => {
+    const exportedFn = module.getResolvedExport('function2');
+    const fn = module.getDeclaration('function2');
+    assert.equal(fn, exportedFn);
+    assert.ok(fn?.isFunctionDeclaration());
+    assert.equal(fn.name, `function2`);
+    assert.equal(fn.summary, `Function 2 summary\nwith wraparound`);
+    assert.equal(fn.description, `Function 2 description\nwith wraparound`);
+    assert.equal(fn.parameters?.length, 3);
+    assert.equal(fn.parameters?.[0].name, 'a');
+    assert.equal(fn.parameters?.[0].description, 'Param a description');
+    assert.equal(fn.parameters?.[0].summary, undefined);
+    assert.equal(fn.parameters?.[0].type?.text, 'string');
+    assert.equal(fn.parameters?.[0].default, undefined);
+    assert.equal(fn.parameters?.[0].rest, false);
+    assert.equal(fn.parameters?.[1].name, 'b');
+    assert.equal(
+      fn.parameters?.[1].description,
+      'Param b description\nwith wraparound'
+    );
+    assert.equal(fn.parameters?.[1].type?.text, 'boolean');
+    assert.equal(fn.parameters?.[1].optional, true);
+    assert.equal(fn.parameters?.[1].default, 'false');
+    assert.equal(fn.parameters?.[1].rest, false);
+    assert.equal(fn.parameters?.[2].name, 'c');
+    assert.equal(fn.parameters?.[2].description, 'Param c description');
+    assert.equal(fn.parameters?.[2].summary, undefined);
+    assert.equal(fn.parameters?.[2].type?.text, 'number[]');
+    assert.equal(fn.parameters?.[2].optional, false);
+    assert.equal(fn.parameters?.[2].default, undefined);
+    assert.equal(fn.parameters?.[2].rest, true);
+    assert.equal(fn.return?.type?.text, 'string');
+    assert.equal(fn.return?.description, 'Function 2 return description');
+    assert.equal(fn.deprecated, 'Function 2 deprecated');
+  });
+
+  test('Default function', ({module}) => {
+    const exportedFn = module.getResolvedExport('default');
+    const fn = module.getDeclaration('default');
+    assert.equal(fn, exportedFn);
+    assert.ok(fn?.isFunctionDeclaration());
+    assert.equal(fn.name, `default`);
+    assert.equal(fn.description, `Default function description`);
+    assert.equal(fn.summary, undefined);
+    assert.equal(fn.parameters?.length, 0);
+    assert.equal(fn.return?.type?.text, 'string');
+    assert.equal(fn.return?.description, 'Default function return description');
+    assert.equal(fn.deprecated, undefined);
+  });
+
+  test.run();
+}

packages/labs/analyzer/test-files/js/functions/functions.js

@@ -0,0 +1,38 @@
+/**
+ * @license
+ * Copyright 2022 Google LLC
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+/**
+ * Function 1 description
+ */
+export function function1() {}
+
+/**
+ * @summary Function 2 summary
+ * with wraparound
+ *
+ * @description Function 2 description
+ * with wraparound
+ *
+ * @param {string} a Param a description
+ * @param {boolean} b Param b description
+ * with wraparound
+ *
+ * @param {number[]} c Param c description
+ * @returns {string} Function 2 return description
+ *
+ * @deprecated Function 2 deprecated
+ */
+export function function2(a, b = false, ...c) {
+  return b ? a : c[0].toFixed();
+}
+
+/**
+ * Default function description
+ * @returns {string} Default function return description
+ */
+export default function () {
+  return 'default';
+}

packages/labs/analyzer/test-files/js/functions/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "@lit-internal/test-functions",
+  "dependencies": {
+    "lit": "^2.0.0"
+  }
+}

packages/labs/analyzer/test-files/ts/functions/package.json

@@ -0,0 +1,6 @@
+{
+  "name": "@lit-internal/test-functions",
+  "dependencies": {
+    "lit": "^2.0.0"
+  }
+}

packages/labs/analyzer/test-files/ts/functions/src/functions.ts

@@ -0,0 +1,38 @@
+/**
+ * @license
+ * Copyright 2022 Google LLC
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+/**
+ * Function 1 description
+ */
+export function function1() {}
+
+/**
+ * @summary Function 2 summary
+ * with wraparound
+ *
+ * @description Function 2 description
+ * with wraparound
+ *
+ * @param a Param a description
+ * @param b Param b description
+ * with wraparound
+ *
+ * @param c Param c description
+ * @returns Function 2 return description
+ *
+ * @deprecated Function 2 deprecated
+ */
+export function function2(a: string, b = false, ...c: number[]) {
+  return b ? a : c[0].toFixed();
+}
+
+/**
+ * Default function description
+ * @returns Default function return description
+ */
+export default function () {
+  return 'default';
+}

packages/labs/analyzer/test-files/ts/functions/tsconfig.json

@@ -0,0 +1,16 @@
+{
+  "compilerOptions": {
+    "target": "es2020",
+    "lib": ["es2020", "DOM"],
+    "module": "ES2020",
+    "rootDir": "./src",
+    "outDir": "./",
+    "moduleResolution": "node",
+    "experimentalDecorators": true,
+    "skipDefaultLibCheck": true,
+    "skipLibCheck": true,
+    "noEmit": true
+  },
+  "include": ["src/**/*.ts"],
+  "exclude": []
+}