3x more startup delay compared to esbuild+node

[j4k0xb]

Acknowledgements

• I read the documentation and searched existing issues to avoid duplicates
• I understand this is a bug tracker and anything other than a proven bug will be closed
• I understand this is a free project and relies on community contributions
• I read and understood the Contribution guide

Minimal reproduction URL

https://stackblitz.com/edit/node-w1u6nxz1?file=benchmark.sh&view=editor

Problem & expected behavior (under 200 words)

• What happened: tsx has noticeable startup delay. StackBlitz: 2.48s, Linux: 0.143s
• What I expected: be roughly as fast as esbuild + node combined. StackBlitz: 0.81s. Linux: 0.034s

After looking into it more, these lines are responsible for about ~50% of the total time:

tsx/src/esm/api/register.ts

Lines 59 to 71 in 26ef600

	module.register(
	// Load new copy of loader so it can be registered multiple times
	`./esm/index.mjs?${Date.now()}`,
	{
	parentURL: import.meta.url,
	data: {
	port: port2,
	namespace: options?.namespace,
	tsconfig: options?.tsconfig,
	} satisfies InitializationOptions,
	transferList: [port2],
	},
	);

Flamegraph (added --cpu-prof flag to run.ts):

Bugs are expected to be fixed by those affected by it

• I'm interested in working on this issue

Compensating engineering work will speed up resolution and support the project

• I'm willing to offer $10 for financial support

[dougg0k]

Maybe tsx could add tsgo support, to make it faster. https://devblogs.microsoft.com/typescript/announcing-typescript-native-previews/