How does bun set up JavaScriptCore to run the entry point script file contents?

[RaisinTen]

When I do bun run script.js, how does bun set up JavaScriptCore for executing the contents of this file? Can someone please help me find the exact location in this repo where this is done? I was looking for a call to evaluateScript but I wasn't able to find any.

[Jarred-Sumner]

This function is where the script execution context is initialized:

bun/src/bun_js.zig

Lines 47 to 66 in 6f59bc7

	pub fn boot(ctx_: Command.Context, file: std.fs.File, entry_path: string) !void {
	var ctx = ctx_;
	JSC.markBinding(@src());
	bun.JSC.initialize();
	js_ast.Expr.Data.Store.create(default_allocator);
	js_ast.Stmt.Data.Store.create(default_allocator);
	var arena = try Arena.init();
	if (!ctx.debug.loaded_bunfig) {
	try bun.CLI.Arguments.loadConfigPath(ctx.allocator, true, "bunfig.toml", &ctx, .RunCommand);
	}
	run = .{
	.vm = try VirtualMachine.init(arena.allocator(), ctx.args, null, ctx.log, null),
	.file = file,
	.arena = arena,
	.ctx = ctx,
	.entry_path = entry_path,
	};

This is where we call the code to evaluate the ESM module:

bun/src/bun.js/javascript.zig

Line 1537 in 6f59bc7

promise = JSModuleLoader.loadAndEvaluateModule(this.global, ZigString.static(main_file_name));

This function is where it does the C++ equivalent of import(path)

bun/src/bun.js/bindings/bindings.cpp

Lines 2048 to 2065 in 6f59bc7

	auto* promise = JSC::loadAndEvaluateModule(globalObject, name, JSC::jsUndefined(), JSC::jsUndefined());
	if (!promise) {
	// usually this is a GC issue
	return jsCast<JSC::JSInternalPromise*>(JSC::JSInternalPromise::rejectedPromise(globalObject, JSC::jsUndefined()));
	}
	JSC::JSNativeStdFunction* resolverFunction = JSC::JSNativeStdFunction::create(
	globalObject->vm(), globalObject, 1, String(), resolverFunctionCallback);
	JSC::JSNativeStdFunction* rejecterFunction = JSC::JSNativeStdFunction::create(
	globalObject->vm(), globalObject, 1, String(),
	[&arg1](JSC::JSGlobalObject* globalObject, JSC::CallFrame* callFrame) -> JSC::EncodedJSValue {
	return JSC::JSValue::encode(
	JSC::JSInternalPromise::rejectedPromise(globalObject, callFrame->argument(0)));
	});
	globalObject->vm().drainMicrotasks();
	auto result = promise->then(globalObject, resolverFunction, rejecterFunction);
	globalObject->vm().drainMicrotasks();