THRIFT-5811: Add ESM support to nodejs codegen
Client: nodejs
Patch: Cameron Martin <cameronm@graphcore.ai>

This closes #3083

This adds a flag to the JS generator to output ES modules instead of CommonJS. This is only valid when targeting node. A lot of the changes here are to test this.

The `testAll.sh` script now generates an ES module version of the services and types, and tests the client and the server with these. This has a few knock-on effects. Firstly, any module that imports a generated ES module must itself be an ES module, since CommonJS modules cannot import ES modules. ES modules also do not support `NODE_PATH`, so instead the tests directory is converted into a node package with a `file:` dependency on the root thrift package.
diff --git a/lib/nodejs/test/test_handler.mjs b/lib/nodejs/test/test_handler.mjs
new file mode 100644
index 0000000..a378fe1
--- /dev/null
+++ b/lib/nodejs/test/test_handler.mjs
@@ -0,0 +1,222 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * 'License'); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * 'AS IS' BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+//This is the server side Node test handler for the standard
+//  Apache Thrift test service.
+import helpers from "./helpers.js";
+import thrift from "thrift";
+
+const ttypes = await helpers.importTypes(`ThriftTest_types`);
+const TException = thrift.Thrift.TException;
+
+function makeSyncHandler() {
+  return function (thing) {
+    return thing;
+  };
+}
+
+const syncHandlers = {
+  testVoid: testVoid,
+  testMapMap: testMapMap,
+  testInsanity: testInsanity,
+  testMulti: testMulti,
+  testException: testException,
+  testMultiException: testMultiException,
+  testOneway: testOneway,
+};
+
+function makeAsyncHandler(label) {
+  return function (thing, result) {
+    thing = syncHandlers[label](thing);
+    result(null, thing);
+  };
+}
+
+const asyncHandlers = {
+  testVoid: testVoidAsync,
+  testMulti: testMultiAsync,
+  testException: testExceptionAsync,
+  testMultiException: testMultiExceptionAsync,
+  testOneway: testOnewayAsync,
+};
+
+const identityHandlers = [
+  "testString",
+  "testBool",
+  "testByte",
+  "testI32",
+  "testI64",
+  "testDouble",
+  "testBinary",
+  "testStruct",
+  "testNest",
+  "testMap",
+  "testStringMap",
+  "testSet",
+  "testList",
+  "testEnum",
+  "testTypedef",
+];
+
+function testVoid() {
+  //console.log('testVoid()');
+}
+
+function testVoidAsync(result) {
+  result(testVoid());
+}
+
+function testMapMap() {
+  const mapmap = [];
+  const pos = [];
+  const neg = [];
+  for (let i = 1; i < 5; i++) {
+    pos[i] = i;
+    neg[-i] = -i;
+  }
+  mapmap[4] = pos;
+  mapmap[-4] = neg;
+
+  return mapmap;
+}
+
+function testInsanity(argument) {
+  //console.log('testInsanity(');
+  //console.log(argument);
+  //console.log(')');
+
+  const first_map = [];
+  const second_map = [];
+
+  first_map[ttypes.Numberz.TWO] = argument;
+  first_map[ttypes.Numberz.THREE] = argument;
+
+  const looney = new ttypes.Insanity();
+  second_map[ttypes.Numberz.SIX] = looney;
+
+  const insane = [];
+  insane[1] = first_map;
+  insane[2] = second_map;
+
+  //console.log('insane result:');
+  //console.log(insane);
+  return insane;
+}
+
+function testMulti(arg0, arg1, arg2) {
+  //console.log('testMulti()');
+
+  const hello = new ttypes.Xtruct();
+  hello.string_thing = "Hello2";
+  hello.byte_thing = arg0;
+  hello.i32_thing = arg1;
+  hello.i64_thing = arg2;
+  return hello;
+}
+
+function testMultiAsync(arg0, arg1, arg2, arg3, arg4, arg5, result) {
+  const hello = testMulti(arg0, arg1, arg2, arg3, arg4, arg5);
+  result(null, hello);
+}
+
+function testException(arg) {
+  //console.log('testException('+arg+')');
+  if (arg === "Xception") {
+    const x = new ttypes.Xception();
+    x.errorCode = 1001;
+    x.message = arg;
+    throw x;
+  } else if (arg === "TException") {
+    throw new TException(arg);
+  } else {
+    return;
+  }
+}
+
+function testExceptionAsync(arg, result) {
+  //console.log('testException('+arg+')');
+  if (arg === "Xception") {
+    const x = new ttypes.Xception();
+    x.errorCode = 1001;
+    x.message = arg;
+    result(x);
+  } else if (arg === "TException") {
+    result(new TException(arg));
+  } else {
+    result(null);
+  }
+}
+
+function testMultiException(arg0, arg1) {
+  //console.log('testMultiException(' + arg0 + ', ' + arg1 + ')');
+  if (arg0 === "Xception") {
+    const x = new ttypes.Xception();
+    x.errorCode = 1001;
+    x.message = "This is an Xception";
+    throw x;
+  } else if (arg0 === "Xception2") {
+    const x2 = new ttypes.Xception2();
+    x2.errorCode = 2002;
+    x2.struct_thing = new ttypes.Xtruct();
+    x2.struct_thing.string_thing = "This is an Xception2";
+    throw x2;
+  }
+
+  const res = new ttypes.Xtruct();
+  res.string_thing = arg1;
+  return res;
+}
+
+function testMultiExceptionAsync(arg0, arg1, result) {
+  //console.log('testMultiException(' + arg0 + ', ' + arg1 + ')');
+  if (arg0 === "Xception") {
+    const x = new ttypes.Xception();
+    x.errorCode = 1001;
+    x.message = "This is an Xception";
+    result(x);
+  } else if (arg0 === "Xception2") {
+    const x2 = new ttypes.Xception2();
+    x2.errorCode = 2002;
+    x2.struct_thing = new ttypes.Xtruct();
+    x2.struct_thing.string_thing = "This is an Xception2";
+    result(x2);
+  } else {
+    const res = new ttypes.Xtruct();
+    res.string_thing = arg1;
+    result(null, res);
+  }
+}
+
+//console.log('testOneway(' + sleepFor + ') => JavaScript (like Rust) never sleeps!');
+function testOneway() {}
+
+function testOnewayAsync(sleepFor) {
+  testOneway(sleepFor);
+}
+
+identityHandlers.forEach(function (label) {
+  syncHandlers[label] = makeSyncHandler(label);
+  asyncHandlers[label] = makeAsyncHandler(label);
+});
+
+["testMapMap", "testInsanity"].forEach(function (label) {
+  asyncHandlers[label] = makeAsyncHandler(label);
+});
+
+export { asyncHandlers as ThriftTestHandler };