Fix #4: add support for Node 18

Author: sebamarynissen

lib/create-loader.js

@@ -60,10 +60,21 @@ class Loader {
 		// For backwards compatibility purposes, we will manually compose 
 		// `format()`, `fetch()` and `transform()` into a `load()` function.
 		const hook = id => (...args) => this.handleStack(id, ...args);
-		const resolve = hook('resolve');
+		const resolve = shortCircuit(hook('resolve'));
 		const getFormat = hook('format');
 		const getSource = hook('fetch');
 
+		// See #4. In Node 18 we now need to specify explicitly that we're 
+		// short-circuiting, which is what this function does.
+		function shortCircuit(fn) {
+			return async function(...args) {
+				return {
+					shortCircuit: true,
+					...await fn(...args),
+				};
+			}
+		}
+
 		// Handling transformation is fundamentally different as we have to 
 		// chain results here.
 		const transformSource = async (source, ctx, node) => {
@@ -109,7 +120,7 @@ class Loader {
 		// higher, which uses the new approach. We only have to export a 
 		// `resolve` and `load` function here, but the difficulty is that the 
 		// `load()` function has to be composed manually!
-		const load = async function(url, ctx, defaultLoad) {
+		const load = shortCircuit(async function(url, ctx, defaultLoad) {
 
 			// If the format was already specified by the resolve hook, we 
 			// won't try to fetch it again. Note that this functionality is 
@@ -143,7 +154,7 @@ class Loader {
 				source: transform.source,
 			};
 
-		};
+		});
 		return { resolve, load };
 
 	}

test/loaders-test.js

@@ -40,7 +40,7 @@ describe('ESM loaders', function() {
 		});
 		await new Promise(resolve => server.listen(resolve));
 		const { port } = server.address();
-		const url = `http://127.0.0.1:${port}`;
+		const url = `http://127.0.0.1:${port}/foo`;
 
 		const run = this.loader('./loaders/http.js');
 		let result = await run(`