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bootstrap: update comments in bootstrap/node.js
The comments in bootstrap/node.js are now out of date due to
recent changes to the bootstrap process. Update them to reflect
the current status.

PR-URL: #44726
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
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joyeecheung authored and danielleadams committed Oct 5, 2022
1 parent 9151439 commit 4e82521af16913ea361990f204e1840ab87e685b
Showing 1 changed file with 32 additions and 16 deletions.
@@ -1,39 +1,55 @@
// Hello, and welcome to hacking node.js!
//
// This file is invoked by `node::RunBootstrapping()` in `src/node.cc`, and is
// responsible for setting up node.js core before executing main scripts
// under `lib/internal/main/`.
// This file is invoked by `Realm::BootstrapNode()` in `src/node_realm.cc`,
// and is responsible for setting up Node.js core before main scripts
// under `lib/internal/main/` are executed.
//
// This file is expected not to perform any asynchronous operations itself
// By default, Node.js binaries come with an embedded V8 startup snapshot
// that is generated at build-time with a `node_mksnapshot` executable.
// The snapshot generation code can be found in `SnapshotBuilder::Generate()`
// from `src/node_snapshotable.cc`.
// This snapshot captures the V8 heap initialized by scripts under
// `lib/internal/bootstrap/`, including this file. When initializing the main
// thread, Node.js deserializes the heap from the snapshot, instead of actually
// running this script and others in `lib/internal/bootstrap/`. To disable this
// behavior, pass `--no-node-snapshot` when starting the process so that
// Node.js actually runs this script to initialize the heap.
//
// This script is expected not to perform any asynchronous operations itself
// when being executed - those should be done in either
// `lib/internal/process/pre_execution.js` or in main scripts. The majority
// of the code here focuses on setting up the global proxy and the process
// object in a synchronous manner.
// As special caution is given to the performance of the startup process,
// many dependencies are invoked lazily.
// `lib/internal/process/pre_execution.js` or in main scripts. It should not
// query any run-time states (e.g. command line arguments, environment
// variables) when being executed - functions in this script that are invoked
// at a later time can, however, query those states lazily.
// The majority of the code here focuses on setting up the global object and
// the process object in a synchronous, environment-independent manner.
//
// Scripts run before this file:
// - `lib/internal/per_context/primordials.js`: to save copies of JavaScript
// - `lib/internal/per_context/primordials.js`: this saves copies of JavaScript
// builtins that won't be affected by user land monkey-patching for internal
// modules to use.
// - `lib/internal/bootstrap/loaders.js`: to setup internal binding and
// - `lib/internal/per_context/domexception.js`: implementation of the
// `DOMException` class.
// - `lib/internal/per_context/messageport.js`: JS-side components of the
// `MessagePort` implementation.
// - `lib/internal/bootstrap/loaders.js`: this sets up internal binding and
// module loaders, including `process.binding()`, `process._linkedBinding()`,
// `internalBinding()` and `BuiltinModule`.
//
// This file is run to bootstrap both the main thread and the worker threads.
// After this file is run, certain properties are setup according to the
// configuration of the Node.js instance using the files in
// The initialization done in this script is included in both the main thread
// and the worker threads. After this, further initialization is done based
// on the configuration of the Node.js instance by executing the scripts in
// `lib/internal/bootstrap/switches/`.
//
// Then, depending on how the Node.js instance is launched, one of the main
// scripts in `lib/internal/main` will be selected by C++ to start the actual
// execution. They may run additional setups exported by
// `lib/internal/process/pre_execution.js` depending on the runtime states.
// `lib/internal/process/pre_execution.js` depending on the run-time states.

'use strict';

// This file is compiled as if it's wrapped in a function with arguments
// passed by node::RunBootstrapping()
// passed by `BuiltinLoader::CompileAndCall()`.
/* global process, require, internalBinding, primordials */

setupPrepareStackTrace();

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