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Nathan Whitaker b74a4f29f2
perf(lsp): Don't retain SourceFileObjects in sourceFileCache longer than necessary (#23258)
The TS language service requests source files via
[getSourceFile](7a25fd5ef0/cli/tsc/99_main_compiler.js (L560)).
In that function, we [unconditionally
add](7a25fd5ef0/cli/tsc/99_main_compiler.js (L613-L614))
the source file to our sourceFileCache. The issue is that we only remove
things from that cache if the source file [becomes out of
date](7a25fd5ef0/cli/tsc/99_main_compiler.js (L777-L783)).
For files that don't get changed, we keep them in the cache
indefinitely. So sometimes we keep SourceFile objects from being GC'ed
because they're retained in our cache, even though TS doesn't refer to
them any more. I see this in pretty much all of the heap snapshots I've
taken.

---

The fix here is pretty direct - just store weak references to the
sourcefiles in the cache. It doesn't really change our caching behavior,
it just prevents us from being the only retainer of a `SourceFile`. I
also split the `sourceFileCache` into a separate cache just for assets,
as we rely on those being alive.

The simpler fix is to only cache assets, but presumably that has a perf
impact.

---
In local testing, this PR reduced the size of the JS heap by about 1 GB
when using `deno lsp` in the Typescript repo.
2024-04-06 19:22:37 -07:00
.cargo feat: bring back WebGPU (#20812) 2023-12-09 01:19:16 +01:00
.devcontainer fix(devcontainer): moved settings to customizations/vscode (#21512) 2023-12-19 13:29:39 +01:00
.github chore: try to fix mac runner (#23214) 2024-04-04 00:02:57 +00:00
bench_util chore: forward v1.42.1 release commit to main (#23162) 2024-04-01 13:35:46 +05:30
cli perf(lsp): Don't retain SourceFileObjects in sourceFileCache longer than necessary (#23258) 2024-04-06 19:22:37 -07:00
ext fix(ext/net): Improve ts types for network APIs (#23228) 2024-04-05 17:01:03 -06:00
runtime FUTURE: remove deprecated APIs within workers (#23220) 2024-04-05 03:27:18 +11:00
tests perf(lsp): use lockfile to reduce npm pkg resolution time (#23247) 2024-04-05 22:33:01 +00:00
tools chore: Make WPT repo shallow (#23205) 2024-04-03 13:40:13 -06:00
.dlint.json chore: update dlint to v0.37.0 for GitHub Actions (#17295) 2023-01-16 17:17:18 +01:00
.dprint.json chore: move tools/node_compat to tests/node_compat/runner (#23025) 2024-04-03 09:24:55 +11:00
.editorconfig chore(tests): Remove vestiges of cli/tests folder (#22712) 2024-03-05 13:49:21 -07:00
.gitattributes chore: move cli/tests/ -> tests/ (#22369) 2024-02-10 20:22:13 +00:00
.gitignore chore: move tools/wpt to tests/wpt/runner (#22545) 2024-03-05 00:41:16 +00:00
.gitmodules chore: Make WPT repo shallow (#23205) 2024-04-03 13:40:13 -06:00
.rustfmt.toml chore: update copyright year to 2023 (#17247) 2023-01-02 21:00:42 +00:00
Cargo.lock perf: reduce allocations in MediaType::from_specifier (#23190) 2024-04-02 17:49:55 -04:00
Cargo.toml perf: reduce allocations in MediaType::from_specifier (#23190) 2024-04-02 17:49:55 -04:00
LICENSE.md chore: update LICENSE.md to 2024 (#21833) 2024-01-06 19:14:38 -05:00
README.md chore: Fix typo in README (#21354) 2023-11-27 21:43:35 +00:00
Releases.md chore: forward v1.42.1 release commit to main (#23162) 2024-04-01 13:35:46 +05:30
rust-toolchain.toml chore: update to Rust 1.76 (#22376) 2024-02-12 03:00:33 +00:00

Deno

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the deno mascot dinosaur standing in the rain

Deno (/ˈdiːnoʊ/, pronounced dee-no) is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults and a great developer experience. It's built on V8, Rust, and Tokio.

Learn more about the Deno runtime in the documentation.

Installation

Install the Deno runtime on your system using one of the commands below. Note that there are a number of ways to install Deno - a comprehensive list of installation options can be found here.

Shell (Mac, Linux):

curl -fsSL https://deno.land/install.sh | sh

PowerShell (Windows):

irm https://deno.land/install.ps1 | iex

Homebrew (Mac):

brew install deno

Chocolatey (Windows):

choco install deno

Build and install from source

Complete instructions for building Deno from source can be found in the manual here.

Your first Deno program

Deno can be used for many different applications, but is most commonly used to build web servers. Create a file called server.ts and include the following TypeScript code:

Deno.serve((_req: Request) => {
  return new Response("Hello, world!");
});

Run your server with the following command:

deno run --allow-net server.ts

This should start a local web server on http://localhost:8000.

Learn more about writing and running Deno programs in the docs.

Additional resources

Contributing

We appreciate your help! To contribute, please read our contributing instructions.