feat(feature-detector): introduces findDependencies() which returns t…

…he list of globals.

docs/pages/packages/feature-detector.mdx

@@ -25,24 +25,45 @@ This package includes built-in TypeScript support.
 
 ## Usage
 
-Here is an example of checking whether a file's default export is a function matching the edge signature, such as:
+Here is a test file. It's in JavaScript, but TypeScript is supported as well.
 
 ```js
+// test.js
+if (typeof process !== 'undefined') {
+  console.log('in node', __dirname)
+} else if (typeof window !== 'undefined') {
+  console.log('in a browser', document)
+}
+setTimeout(() => console.log('setTimeout is not a global, nor console'), 0)
+
 export default function () {
   return Response.json({ message: 'hello world!' })
 }
 ```
 
+In the code snippet bellow, we're checking:
+
+1. whether this file is a function matching the edge signature
+2. globals used, that are not provided by the Edge Runtime
+
 ```ts
-import { hasEdgeSignature } from '@edge-runtime/feature-detector'
+import {
+  hasEdgeSignature,
+  findDependencies,
+} from '@edge-runtime/feature-detector'
 
 const sourceFilePath = './test.js' // could be TypeScript as well. Must be in current working directory
 
+// 1
 if (hasEdgeSignature(sourceFilePath)) {
-  console.log(`${sourcefilePath} can run on the edge``)
+  console.log(`${sourcefilePath} can run on the edge`)
 }
+// 2
+console.log(findDependencies(sourceFilePath).globals)
 ```
 
+Z
+
 ## API
 
 <Callout type='warning' emoji='⚠️'>

packages/feature-detector/package.json

@@ -27,12 +27,16 @@
     "ts-morph": "17.0.1"
   },
   "devDependencies": {
+    "axios": "0.27.2",
     "jest-text-transformer": "1.0.4",
     "next": "13",
     "react": "18",
     "react-dom": "18",
     "tsup": "6"
   },
+  "peerDependencies": {
+    "esbuild": "^0.16.16"
+  },
   "engines": {
     "node": ">=14"
   },
@@ -42,7 +46,6 @@
   "scripts": {
     "build": "tsup",
     "clean:build": "rm -rf dist",
-    "patch-type-definition": "ts-node scripts/patch-type-definition.ts",
     "prebuild": "pnpm run clean:build",
     "test": "jest"
   },

packages/feature-detector/scripts/build-fixtures.ts

@@ -0,0 +1,31 @@
+// run with ts-node
+import { build } from 'esbuild'
+import { readdir, readFile, writeFile } from 'node:fs/promises'
+import { join } from 'node:path'
+
+const fixtureFolder = join(__dirname, '../test/fixtures')
+const resultExtension = '.out.js'
+
+async function transpileAll() {
+  for (const file of await readdir(fixtureFolder)) {
+    if (!file.endsWith(resultExtension)) {
+      await transpileFile(file)
+    }
+  }
+}
+
+async function transpileFile(file: string) {
+  const filePath = join(fixtureFolder, file)
+  await build({
+    entryPoints: [filePath],
+    bundle: true,
+    outfile: filePath.replace(/\..+$/, resultExtension),
+  })
+}
+
+transpileAll()
+  .then(() => process.exit(0))
+  .catch((error) => {
+    console.log('Errored', error)
+    process.exit(1)
+  })

packages/feature-detector/src/find-dependencies.ts

@@ -0,0 +1,37 @@
+import { Project, ts } from 'ts-morph'
+import { buildProject } from './utils/project'
+
+/**
+ * Find the list of globals used by source files in the provided project.
+ * Analyzed source files can be filtered by provided a list of glob patterns (default to all TypeScript and JavaScript files, excluding type definitions)
+ */
+export function findDependencies(
+  sourcePath: string,
+  project: Project = buildProject()
+): {
+  globals: string[]
+} {
+  const globals = new Set<string>()
+  const sourceFile = project.addSourceFileAtPath(sourcePath)
+  const program = project.getProgram().compilerObject
+  const diagnostics = program.getSemanticDiagnostics(sourceFile.compilerNode)
+  for (const { code, messageText } of diagnostics) {
+    if (
+      // see all messages: https://github.com/microsoft/TypeScript/blob/main/src/compiler/diagnosticMessages.json#L1631
+      code === 2304 ||
+      code === 2311 ||
+      code === 2552 ||
+      (code >= 2562 && code <= 2563) ||
+      (code >= 2580 && code <= 2584) ||
+      (code >= 2591 && code <= 2593)
+    ) {
+      const match = ts
+        .flattenDiagnosticMessageText(messageText, '\n')
+        .match(/^Cannot find name '([^']+)'\./)
+      if (match) {
+        globals.add(match[1])
+      }
+    }
+  }
+  return { globals: [...globals] }
+}

packages/feature-detector/src/index.ts

@@ -1 +1,2 @@
+export * from './find-dependencies'
 export * from './has-edge-signature'

packages/feature-detector/src/utils/project.ts

@@ -8,10 +8,12 @@ import typeDefinitionContent from './type-definition.txt'
 export function buildProject() {
   const project = new Project({
     compilerOptions: {
+      types: [], // does not load node.js types to only rely on types provided by Edge runtime
       allowJs: true,
+      checkJs: true,
     },
   })
   project.createSourceFile('node_modules/index.d.ts', typeDefinitionContent)
-  project.addDirectoryAtPathIfExists('.')
+  project.addDirectoryAtPath('.')
   return project
 }