feat: export metadata object in local stage 2 (#126)

* feat: add `metadata` object to local stage 2

* chore: add comment

* chore: use file URL in test

* chore: adjust test for Node <14

* chore: run stage 2 in Deno

node/formats/javascript.ts

@@ -108,24 +108,30 @@ const getLocalEntryPoint = (
   }: GetLocalEntryPointOptions,
 ) => {
   const bootImport = `import { boot } from "${getBootstrapURL()}";`
-  const declaration = `const functions = {};`
-  const imports = functions.map(
-    (func) => `
-  try {
-    const { default: func } = await import("${pathToFileURL(func.path)}");
-
-    if (typeof func === "function") {
-      functions["${func.name}"] = func;
-    } else {
-      console.log(${JSON.stringify(formatExportTypeError(func.name))});
+  const declaration = `const functions = {}; const metadata = {};`
+  const imports = functions.map((func) => {
+    const url = pathToFileURL(func.path)
+    const metadata = {
+      url,
     }
-  } catch (error) {
-    console.log(${JSON.stringify(formatImportError(func.name))});
-    console.error(error);
-  }
-  `,
-  )
-  const bootCall = `boot(functions);`
+
+    return `
+      try {
+        const { default: func } = await import("${url}");
+    
+        if (typeof func === "function") {
+          functions["${func.name}"] = func;
+          metadata["${func.name}"] = ${JSON.stringify(metadata)}
+        } else {
+          console.log(${JSON.stringify(formatExportTypeError(func.name))});
+        }
+      } catch (error) {
+        console.log(${JSON.stringify(formatImportError(func.name))});
+        console.error(error);
+      }
+      `
+  })
+  const bootCall = `boot(functions, metadata);`
 
   return [bootImport, declaration, ...imports, bootCall].join('\n\n')
 }
@@ -150,4 +156,4 @@ const getProductionEntryPoint = (functions: EdgeFunction[]) => {
   return [bootImport, importLines, exportDeclaration, defaultExport].join('\n\n')
 }
 
-export { bundleJS as bundle, generateStage2, getBootstrapURL }
+export { bundleJS as bundle, generateStage2, getBootstrapURL, getLocalEntryPoint }

test/node/stage_2.ts

@@ -0,0 +1,67 @@
+import { promises as fs } from 'fs'
+import { join } from 'path'
+import process from 'process'
+import { pathToFileURL } from 'url'
+
+import test from 'ava'
+import del from 'del'
+import { execa } from 'execa'
+import semver from 'semver'
+import tmp from 'tmp-promise'
+
+import { getLocalEntryPoint } from '../../node/formats/javascript.js'
+
+test('`getLocalEntryPoint` returns a valid stage 2 file for local development', async (t) => {
+  const { path: tmpDir } = await tmp.dir()
+
+  // This is a fake bootstrap that we'll create just for the purpose of logging
+  // the functions and the metadata that are sent to the `boot` function.
+  const printer = `
+    export const boot = async (functions, metadata) => {
+      const responses = {}
+
+      for (const name in functions) {
+        responses[name] = await functions[name]()
+      }
+
+      console.log(JSON.stringify({ responses, metadata }))
+    }
+  `
+  const printerPath = join(tmpDir, 'printer.mjs')
+
+  await fs.writeFile(printerPath, printer)
+  process.env.NETLIFY_EDGE_BOOTSTRAP = pathToFileURL(printerPath).toString()
+
+  const functions = [
+    { name: 'func1', path: join(tmpDir, 'func1.mjs'), response: 'Hello from function 1' },
+    { name: 'func2', path: join(tmpDir, 'func2.mjs'), response: 'Hello from function 2' },
+  ]
+
+  for (const func of functions) {
+    const contents = `export default () => ${JSON.stringify(func.response)}`
+
+    await fs.writeFile(func.path, contents)
+  }
+
+  const stage2 = getLocalEntryPoint(
+    functions.map(({ name, path }) => ({ name, path })),
+    {},
+  )
+  const stage2Path = join(tmpDir, 'stage2.mjs')
+
+  await fs.writeFile(stage2Path, stage2)
+
+  const { stdout, stderr } = await execa('deno', ['run', '--allow-all', stage2Path])
+
+  t.is(stderr, '')
+
+  const { metadata, responses } = JSON.parse(stdout)
+
+  for (const func of functions) {
+    t.is(responses[func.name], func.response)
+    t.is(metadata[func.name].url, pathToFileURL(func.path).toString())
+  }
+
+  await del(tmpDir, { force: true })
+  delete process.env.NETLIFY_EDGE_BOOTSTRAP
+})