[fix] Improve performance by using trimRight() instead of regex replace

[ota-meshi]

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• [x] It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs
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Tests

• [x] Run the tests with npm test and lint the project with npm run lint

close #7675

This PR uses trimRight() instead of replace(/\s+$/, '') to improve parsing performance.

See the https://github.com/sveltejs/svelte/issues/7675#issuecomment-1179995722 for issues with the original regex.

If you know how to add a test to check performance, please let me know. I ran the following test locally and I checked that it would improve performance.

import { parse } from '../../compiler.js';
describe('improve performance', () => {
	it('parse', () => {
		parse(`<div>${' '.repeat(1000000)}</div>`);
	});
});

[benmccann]

I wonder if the benchmark would give different results after @ivanhofer's change: https://github.com/sveltejs/svelte/pull/7716

[ota-meshi]

I don't think the #7716 change will change the benchmark results. This fix is related to backtracking. See https://github.com/sveltejs/svelte/issues/7675#issuecomment-1179995722.

[ivanhofer]

@ota-meshi what about using trimLeft() here: https://github.com/ota-meshi/svelte/blob/use-trim-right/src/compiler/compile/render_ssr/index.ts#L231?

[ota-meshi]

/^\s+/ don't backtrack, so we don't need to fix that. However, I think it makes sense to use trimLeft() for the purpose of unifying code style. I think it depends on what the team prefers.

[shirotech]

Seems to have ticked all the boxes, any chance this can be merged soon?