Add an API for fast HTML escaping

[bartlomieju]

In various benchmarks that @littledivy and @billywhizz did we see that escaping HTML that a huge chunk of time in React SSR examples.

It's clearly a bottleneck that could be addressed by having a dedicated API for escaping HTML (probably as an op implemented in Rust).

This should allow us to top various React SSR benchmarks.

[cmoog]

@littledivy @bartlomieju
For API cleanliness of the top-level Deno namespace, I wonder if it would be smart to use a namespace specifically for these non-WebAPI and non-io operations that are only implemented in native code for performance reasons.

Some potential options

• Deno.native.escapeHtml
• Deno.fast.escapeHtml

[kidonng]

@cmoog While I don't find the idea of stuffing niche APIs under Deno namespace interesting either, those options are worse:

• Most APIs under Deno namespace are implemented natively so Deno.native is redundant.
• Deno.fast just doesn't make sense. People expect things to be fast. There's no Deno.slow, nor is anything else under Deno slow.

[cmoog]

@kidonng

Deno.fast just doesn't make sense. People expect things to be fast. There's no Deno.slow, nor is anything else under Deno slow.

Deno.fast answers the question "Why should I use Deno.escapeHtml vs. a pure JS impl. It's clear why one would use Deno.fast.escapeHtml vs. some other escapeHtml: because it's faster. A few more options

• Deno.optimized
• Deno.perf

A pure JS escapeHtml is not fast. As compared to Deno.escapeHtml, it is slow. That's the whole point. Without any semantics that make this distinction apparent to the user, it's confusing what the difference is.

[crowlKats]

A) we don't namespace. the only namespaces we have are the Deno one, and the Deno.errors, and the latter one is an exception of the rule

B)

A pure JS escapeHtml is not fast. As compared to Deno.escapeHtml it is slow.

Web APIs arent implemented in pure JS (except a few that wouldnt make sense otherwise). most of the web APIs have rust code behind them. There is no distinction and it makes no sense to have multiple APIs for the same thing.

[kidonng]

Without any semantics that make this distinction apparent to the user, it's confusing what the difference is.

Deno namespace is the difference. You can do the same bikeshedding about Deno.test and some other test library.

[cmoog]

Deno namespace is the difference. You can do the same bikeshedding about Deno.test and some other test library.

Fair. I retract.

[lucacasonato]

Qwik also has a escapeAttr that may be optimizable the same way: https://github.com/BuilderIO/qwik/blob/8adb568bcb5ea829e266cf75e4fc856dcf93bcf3/packages/qwik/src/core/render/ssr/render-ssr.ts#L826-L837