test: cover loading an ESM loader via require() on Node.js 22.12+

test/fixtures/esm-invalid-loader.mjs

@@ -0,0 +1 @@
+export default "";

test/fixtures/esm-pitching-loader.mjs

@@ -0,0 +1,3 @@
+export function pitch(remainingRequest, previousRequest) {
+	return [remainingRequest, previousRequest].join(":");
+}

test/fixtures/esm-raw-loader.mjs

@@ -0,0 +1,8 @@
+export default function (source) {
+	return Buffer.from(
+		source.toString("hex") + source.toString("utf-8"),
+		"utf-8"
+	);
+}
+
+export const raw = true;

test/runLoaders.js

@@ -738,6 +738,154 @@ describe("runLoaders", () => {
 			);
 		});
 	}
+
+	const [nodeMajor, nodeMinor] = process.versions.node.split(".").map(Number);
+	// `require(esm)` is enabled by default starting from Node.js 22.12.0
+	if (nodeMajor > 22 || (nodeMajor === 22 && nodeMinor >= 12)) {
+		it("should load an esm loader using require()", (done) => {
+			runLoaders(
+				{
+					resource: path.resolve(fixtures, "resource.bin"),
+					loaders: [path.resolve(fixtures, "esm-loader.mjs")],
+				},
+				(err, result) => {
+					if (err) return done(err);
+					result.result.should.be.eql(["resource-esm"]);
+					result.cacheable.should.be.eql(true);
+					result.fileDependencies.should.be.eql([
+						path.resolve(fixtures, "resource.bin"),
+					]);
+					result.contextDependencies.should.be.eql([]);
+					done();
+				}
+			);
+		});
+	}
+
+	if (Number(process.versions.modules) >= 83) {
+		it("should load a commonjs loader using import()", (done) => {
+			runLoaders(
+				{
+					resource: path.resolve(fixtures, "resource.bin"),
+					loaders: [
+						{
+							loader: path.resolve(fixtures, "simple-loader.js"),
+							type: "module",
+						},
+					],
+				},
+				(err, result) => {
+					if (err) return done(err);
+					result.result.should.be.eql(["resource-simple"]);
+					result.cacheable.should.be.eql(true);
+					result.fileDependencies.should.be.eql([
+						path.resolve(fixtures, "resource.bin"),
+					]);
+					result.contextDependencies.should.be.eql([]);
+					done();
+				}
+			);
+		});
+
+		it("should process an esm pitching loader using import()", (done) => {
+			runLoaders(
+				{
+					resource: path.resolve(fixtures, "resource.bin"),
+					loaders: [
+						path.resolve(fixtures, "simple-loader.js"),
+						{
+							loader: path.resolve(fixtures, "esm-pitching-loader.mjs"),
+							type: "module",
+						},
+						path.resolve(fixtures, "simple-async-loader.js"),
+					],
+				},
+				(err, result) => {
+					if (err) return done(err);
+					result.result.should.be.eql([
+						`${path.resolve(fixtures, "simple-async-loader.js")}!${path.resolve(
+							fixtures,
+							"resource.bin"
+						)}:${path.resolve(fixtures, "simple-loader.js")}-simple`,
+					]);
+					result.cacheable.should.be.eql(true);
+					result.fileDependencies.should.be.eql([]);
+					result.contextDependencies.should.be.eql([]);
+					done();
+				}
+			);
+		});
+
+		it("should process an esm raw loader using import()", (done) => {
+			runLoaders(
+				{
+					resource: path.resolve(fixtures, "bom.bin"),
+					loaders: [
+						{
+							loader: path.resolve(fixtures, "esm-raw-loader.mjs"),
+							type: "module",
+						},
+					],
+				},
+				(err, result) => {
+					if (err) return done(err);
+					result.result[0].toString("utf8").should.be.eql("efbbbf62c3b66dböm");
+					done();
+				}
+			);
+		});
+
+		it("should not return dependencies when an esm loader is not found", (done) => {
+			runLoaders(
+				{
+					resource: path.resolve(fixtures, "resource.bin"),
+					loaders: [
+						{
+							loader: path.resolve(fixtures, "does-not-exist-loader.mjs"),
+							type: "module",
+						},
+					],
+				},
+				(err, result) => {
+					err.should.be.instanceOf(Error);
+					result.should.be.eql({
+						cacheable: false,
+						fileDependencies: [],
+						contextDependencies: [],
+						missingDependencies: [],
+					});
+					done();
+				}
+			);
+		});
+
+		it("should not return dependencies when an esm loader has an invalid default export", (done) => {
+			runLoaders(
+				{
+					resource: path.resolve(fixtures, "resource.bin"),
+					loaders: [
+						{
+							loader: path.resolve(fixtures, "esm-invalid-loader.mjs"),
+							type: "module",
+						},
+					],
+				},
+				(err, result) => {
+					err.should.be.instanceOf(Error);
+					err.message.should.match(
+						/esm-invalid-loader\.mjs' is not a loader \(must have normal or pitch function\)$/
+					);
+					result.should.be.eql({
+						cacheable: false,
+						fileDependencies: [],
+						contextDependencies: [],
+						missingDependencies: [],
+					});
+					done();
+				}
+			);
+		});
+	}
 	it("should support escaping in resource", (done) => {
 		runLoaders(
 			{