es modules: implement npm spec

- add -m, --module for preloading esm - Refactored startup for readability. - We can now syntax-check ESM files in addition to commonjs files. - We now handle file path resolution the way the commonjs code path does. - Removed --loader. - Removed frozen "safe" promises and maps.

Author: chrisdickinson

.eslintrc.yaml

@@ -12,11 +12,6 @@ parser: babel-eslint
 parserOptions:
  sourceType: script
 
-overrides:
- - files: ["doc/api/esm.md", "*.mjs", "test/es-module/test-esm-example-loader.js"]
- parserOptions:
- sourceType: module
-
 rules:
  # Possible Errors
  # http://eslint.org/docs/rules/#possible-errors
@@ -209,3 +204,8 @@ globals:
  LTTNG_NET_SERVER_CONNECTION: false
  LTTNG_NET_STREAM_END: false
  internalBinding: false
+
+overrides:
+ - files: [ "esm.md" ]
+ parserOptions:
+ sourceType: module

lib/internal/bootstrap_node.js

@@ -108,7 +108,6 @@
  'ExperimentalWarning', undefined);
  }
 
-
  // There are various modes that Node can run in. The most common two
  // are running from a script and running the REPL - but there are a few
  // others like the debugger or running --eval arguments. Here we decide
@@ -123,8 +122,11 @@
  NativeModule.require('_third_party_main');
  perf.markMilestone(NODE_PERFORMANCE_MILESTONE_THIRD_PARTY_MAIN_END);
  });
+ return;
+ }
 
- } else if (process.argv[1] === 'inspect' || process.argv[1] === 'debug') {
+ // Are we debugging?
+ if (process.argv[1] === 'inspect' || process.argv[1] === 'debug') {
  if (process.argv[1] === 'debug') {
  process.emitWarning(
  '`node debug` is deprecated. Please use `node inspect` instead.',
@@ -135,115 +137,149 @@
  process.nextTick(function() {
  NativeModule.require('internal/deps/node-inspect/lib/_inspect').start();
  });
+ return;
+ }
 
- } else if (process.profProcess) {
+ // Are we handling profiling output?
+ if (process.profProcess) {
  NativeModule.require('internal/v8_prof_processor');
+ return;
+ }
 
- } else {
- // There is user code to be run
-
- // If this is a worker in cluster mode, start up the communication
- // channel. This needs to be done before any user code gets executed
- // (including preload modules).
- if (process.argv[1] && process.env.NODE_UNIQUE_ID) {
- perf.markMilestone(NODE_PERFORMANCE_MILESTONE_CLUSTER_SETUP_START);
- const cluster = NativeModule.require('cluster');
- cluster._setupWorker();
- perf.markMilestone(NODE_PERFORMANCE_MILESTONE_CLUSTER_SETUP_END);
- // Make sure it's not accidentally inherited by child processes.
- delete process.env.NODE_UNIQUE_ID;
+ // If we reach here, we have user code to run. What sort of user code?
+ const isClusterWorker = process.argv[1] && process.env.NODE_UNIQUE_ID;
+ const isEvalTarget = process._eval != null && !process._forceRepl;
+ const isFileTarget = process.argv[1] && process.argv[1] !== '-';
+
+ // If this is a worker in cluster mode, start up the communication
+ // channel. This needs to be done before any user code gets executed
+ // (including preload modules).
+ if (isClusterWorker) {
+ perf.markMilestone(NODE_PERFORMANCE_MILESTONE_CLUSTER_SETUP_START);
+ const cluster = NativeModule.require('cluster');
+ cluster._setupWorker();
+ perf.markMilestone(NODE_PERFORMANCE_MILESTONE_CLUSTER_SETUP_END);
+ // Make sure it's not accidentally inherited by child processes.
+ delete process.env.NODE_UNIQUE_ID;
+ }
+
+ let loadUserFile = () => {
+ perf.markMilestone(NODE_PERFORMANCE_MILESTONE_MODULE_LOAD_START);
+ // make process.argv[1] into a full path
+ const path = NativeModule.require('path');
+ process.argv[1] = path.resolve(process.argv[1]);
+
+ const Module = NativeModule.require('module');
+
+ // check if user passed `-c` or `--check` arguments to Node.
+ if (process._syntax_check_only != null) {
+ const fs = NativeModule.require('fs');
+ // read the source
+ const filename = Module._resolveFilename(process.argv[1]);
+ var source = fs.readFileSync(filename, 'utf-8');
+ checkScriptSyntax(source, filename);
+ process.exit(0);
  }
 
- if (process._eval != null && !process._forceRepl) {
+ return Module;
+ };
+
+ if (isEvalTarget || !isFileTarget) {
+ loadUserFile = () => {
  perf.markMilestone(NODE_PERFORMANCE_MILESTONE_MODULE_LOAD_START);
  perf.markMilestone(NODE_PERFORMANCE_MILESTONE_MODULE_LOAD_END);
-  // User passed '-e' or '--eval' arguments to Node without '-i' or
-  // '--interactive'
+ };
+ }
 
- perf.markMilestone(
- NODE_PERFORMANCE_MILESTONE_PRELOAD_MODULE_LOAD_START);
- preloadModules();
- perf.markMilestone(NODE_PERFORMANCE_MILESTONE_PRELOAD_MODULE_LOAD_END);
+ const MaybeModule = loadUserFile();
 
+ if (isEvalTarget) {
+ // User passed '-e' or '--eval' arguments to Node without '-i' or
+ // '--interactive'
+ preloadModules(() => {
  const internalModule = NativeModule.require('internal/module');
  internalModule.addBuiltinLibsToObject(global);
  evalScript('[eval]');
- } else if (process.argv[1] && process.argv[1] !== '-') {
- perf.markMilestone(NODE_PERFORMANCE_MILESTONE_MODULE_LOAD_START);
- // make process.argv[1] into a full path
- const path = NativeModule.require('path');
- process.argv[1] = path.resolve(process.argv[1]);
+ });
+ } else if (isFileTarget) {
+ preloadModules(() => MaybeModule.runMain());
+ } else {
+ preloadModules(() => runRepl());
+ }
 
-  const Module = NativeModule.require('module');
+ // This is the end of the startup code.
 
- // check if user passed `-c` or `--check` arguments to Node.
- if (process._syntax_check_only != null) {
- const fs = NativeModule.require('fs');
- // read the source
- const filename = Module._resolveFilename(process.argv[1]);
- var source = fs.readFileSync(filename, 'utf-8');
- checkScriptSyntax(source, filename);
- process.exit(0);
+ // Load preload modules
+ function preloadModules(next) {
+ perf.markMilestone(
+ NODE_PERFORMANCE_MILESTONE_PRELOAD_MODULE_LOAD_START);
+ if (process._preload_modules) {
+ NativeModule.require('module')
+ ._preloadModules(process._preload_modules);
+ }
+
+ if (process._preload_es_modules) {
+ NativeModule.require('module')
+ ._preloadESModules(process._preload_es_modules).then(() => {
+ perf.markMilestone(
+ NODE_PERFORMANCE_MILESTONE_PRELOAD_MODULE_LOAD_END);
+ next();
+ perf.markMilestone(NODE_PERFORMANCE_MILESTONE_BOOTSTRAP_COMPLETE);
+ }).catch((err) => {
+ process._rawDebug(err.stack);
+ process.exit(1);
+ });
+ return;
+ }
+
+ perf.markMilestone(NODE_PERFORMANCE_MILESTONE_PRELOAD_MODULE_LOAD_END);
+ next();
+ perf.markMilestone(NODE_PERFORMANCE_MILESTONE_BOOTSTRAP_COMPLETE);
+ }
+ }
+
+ function runRepl() {
+ // If -i or --interactive were passed, or stdin is a TTY.
+ if (process._forceRepl || NativeModule.require('tty').isatty(0)) {
+ // REPL
+ const cliRepl = NativeModule.require('internal/repl');
+ cliRepl.createInternalRepl(process.env, function(err, repl) {
+ if (err) {
+ throw err;
  }
- perf.markMilestone(NODE_PERFORMANCE_MILESTONE_MODULE_LOAD_END);
- perf.markMilestone(
- NODE_PERFORMANCE_MILESTONE_PRELOAD_MODULE_LOAD_START);
- preloadModules();
- perf.markMilestone(
- NODE_PERFORMANCE_MILESTONE_PRELOAD_MODULE_LOAD_END);
- Module.runMain();
- } else {
- perf.markMilestone(NODE_PERFORMANCE_MILESTONE_MODULE_LOAD_START);
- perf.markMilestone(NODE_PERFORMANCE_MILESTONE_MODULE_LOAD_END);
- perf.markMilestone(
- NODE_PERFORMANCE_MILESTONE_PRELOAD_MODULE_LOAD_START);
- preloadModules();
- perf.markMilestone(
- NODE_PERFORMANCE_MILESTONE_PRELOAD_MODULE_LOAD_END);
- // If -i or --interactive were passed, or stdin is a TTY.
- if (process._forceRepl || NativeModule.require('tty').isatty(0)) {
- // REPL
- const cliRepl = NativeModule.require('internal/repl');
- cliRepl.createInternalRepl(process.env, function(err, repl) {
- if (err) {
- throw err;
- }
- repl.on('exit', function() {
- if (repl._flushing) {
- repl.pause();
- return repl.once('flushHistory', function() {
- process.exit();
- });
- }
+ repl.on('exit', function() {
+ if (repl._flushing) {
+ repl.pause();
+ return repl.once('flushHistory', function() {
  process.exit();
  });
- });
-
- if (process._eval != null) {
- // User passed '-e' or '--eval'
- evalScript('[eval]');
  }
- } else {
-  // Read all of stdin - execute it.
-  process.stdin.setEncoding('utf8');
+  process.exit();
+ });
+ });
 
- var code = '';
- process.stdin.on('data', function(d) {
- code += d;
- });
+ if (process._eval != null) {
+ // User passed '-e' or '--eval'
+ evalScript('[eval]');
+ }
+ } else {
+ // Read all of stdin - execute it.
+ process.stdin.setEncoding('utf8');
 
- process.stdin.on('end', function() {
- if (process._syntax_check_only != null) {
- checkScriptSyntax(code, '[stdin]');
- } else {
- process._eval = code;
- evalScript('[stdin]');
- }
- });
+ var code = '';
+ process.stdin.on('data', function(d) {
+ code += d;
+ });
+
+ process.stdin.on('end', function() {
+ if (process._syntax_check_only != null) {
+ checkScriptSyntax(code, '[stdin]');
+ } else {
+ process._eval = code;
+ evalScript('[stdin]');
  }
- }
+ });
  }
- perf.markMilestone(NODE_PERFORMANCE_MILESTONE_BOOTSTRAP_COMPLETE);
  }
 
  function setupProcessObject() {
@@ -487,26 +523,27 @@
  process._tickCallback();
  }
 
- // Load preload modules
- function preloadModules() {
- if (process._preload_modules) {
- NativeModule.require('module')._preloadModules(process._preload_modules);
- }
- }
-
  function checkScriptSyntax(source, filename) {
+ // We need to determine the kind of module this is (commonjs or esm)
+ // and load it the right way.
+
  const Module = NativeModule.require('module');
  const vm = NativeModule.require('vm');
  const internalModule = NativeModule.require('internal/module');
+ const { ModuleWrap } = NativeModule.require('internal/loader/ModuleWrap');
 
- // remove Shebang
+ const mode = Module.guessModuleMode(filename, source);
  source = internalModule.stripShebang(source);
- // remove BOM
  source = internalModule.stripBOM(source);
- // wrap it
- source = Module.wrap(source);
- // compile the script, this will throw if it fails
- new vm.Script(source, { displayErrors: true, filename });
+ if (mode === 'esm') {
+ new ModuleWrap(source, filename);
+ // this throws if a syntax error
+ } else {
+ // We are legacy commons.
+ source = Module.wrap(source);
+ // Compile the script. This will throw if it fails.
+ new vm.Script(source, { displayErrors: true, filename });
+ }
  }
 
  // Below you find a minimal module system, which is used to load the node

lib/internal/errors.js

@@ -263,6 +263,9 @@ E('ERR_ASYNC_TYPE', 'Invalid name for async "type": %s');
 E('ERR_BUFFER_OUT_OF_BOUNDS', bufferOutOfBounds);
 E('ERR_BUFFER_TOO_LARGE',
  `Cannot create a Buffer larger than 0x${kMaxLength.toString(16)} bytes`);
+E('ERR_CANNOT_IMPORT_LEGACY_MODULE',
+ 'Cannot import module previously loaded as legacy module: %s');
+E('ERR_CANNOT_REQUIRE_ESM', 'Cannot require module previously loaded as ES module: %s');
 E('ERR_CANNOT_WATCH_SIGINT', 'Cannot watch for SIGINT signals');
 E('ERR_CHILD_CLOSED_BEFORE_REPLY', 'Child closed before reply received');
 E('ERR_CHILD_PROCESS_IPC_REQUIRED',