fix: modify module loader to look in parent directories (#144)

This resolves issues where function source may be in a subdirectory, for
example `./build` in a TypeScript project.

Fixes: #143

Signed-off-by: Lance Ball <lball@redhat.com>

.github/workflows/ci.yml

@@ -8,10 +8,11 @@ on:
 
 jobs:
  lts:
- runs-on: ubuntu-latest
  strategy:
  matrix:
  node-version: [14.x, 16.x]
+ os: [ubuntu-latest, windows-latest]
+ runs-on: ${{ matrix.os }}
  steps:
  - uses: actions/checkout@v2
  - name: Use Node.js ${{ matrix.node-version }}
@@ -23,7 +24,10 @@ jobs:
  - run: npm test
 
  current:
- runs-on: ubuntu-latest
+ strategy:
+ matrix:
+ os: [ubuntu-latest, windows-latest]
+ runs-on: ${{ matrix.os }}
  steps:
  - uses: actions/checkout@v2
  - name: Use Node.js 18.x
@@ -36,6 +40,6 @@ jobs:
  - uses: codecov/codecov-action@v3
  with:
  files: coverage/lcov.info
- name: ${{ matrix.node-version }}
+ name: lts ${{ matrix.os }}
  fail_ci_if_error: true
  verbose: true

.gitignore

@@ -1,3 +1,4 @@
 node_modules
 .nyc_output
 coverage
+test/fixtures/*/package-lock.json

lib/function-loader.js

@@ -1,10 +1,15 @@
+const fs = require('fs');
 const path = require('path');
 
 // This is the way to import es modules inside a CJS module
 const dynamicImport = new Function('modulePath', 'return import(modulePath)');
 
 async function loadFunction(filePath) {
  if (isESM(filePath)) {
+ if (process.platform === 'win32') {
+ // Windows requires the file path to be a URL
+ filePath = `file:///${filePath}`;
+ }
  code = await dynamicImport(filePath);
  } else {
  code = require(filePath);
@@ -25,14 +30,29 @@ function isESM(filePath) {
  }
 
  // find the functions package.json and see if it has a type field
- const functionPkg = require(path.join(pathParsed.dir, 'package.json'));
- if (functionPkg.type === 'module') {
- return true;
+ // look in the parent directory if the function is in a subdirectory
+ let dir = pathParsed.dir;
+ const rootDir = path.parse(process.cwd()).root;
+ while (!hasPackageJson(dir)) {
+ if (dir === rootDir) return false;
+ dir = path.dirname(dir);
  }
 
- // Should default to CJS
- return false;
+ // Load the package.json and check the type field
+ // Put this in a try/catch in case the package.json is invalid
+ let pkgPath = path.join(dir, 'package.json');
+ try {
+ const functionPkg = JSON.parse(fs.readFileSync(pkgPath, 'utf8'));
+ return functionPkg.type === 'module';
+ } catch(e) {
+ console.warn(e);
+ return false;
+ }
 }
 
+function hasPackageJson(dir) {
+ const pkgPath = path.join(dir, 'package.json');
+ return fs.existsSync(pkgPath);
+}
 
 module.exports = exports = { loadFunction };

test/fixtures/esm-module-type-up-dir/build/index.js

@@ -0,0 +1,2 @@
+const handle = async _ => 'ok';
+export { handle };

test/fixtures/esm-module-type-up-dir/package.json

@@ -0,0 +1,5 @@
+{
+ "name": "esm-module-type-module",
+ "version": "1.0.0",
+ "type": "module"
+}

test/test-function-loading.js

@@ -21,3 +21,9 @@ test('Loads an ESM function with the type=module in the package.json', async t =
  t.equal(typeof fn.handle, 'function');
  t.pass('ESM module with a type=module in the package.json');
 });
+
+test('Loads an ESM function with the type=module in package.json in a parent dir and a .js extension', async t => {
+ const fn = await loadFunction(path.join(fixtureDir, 'esm-module-type-up-dir', 'build', 'index.js'));
+ t.equal(typeof fn.handle, 'function');
+ t.pass('ESM module with a type=module in a package.json in parent directory');
+});