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denoland-deno/ext/node/polyfills/_fs/_fs_exists.ts
Divy Srivastava 078def0ff8
perf(ext/node): optimize fs.exists[Sync] (#24613)
Use `access` on *nix and `GetFileAttributesW` on Windows.

[Benchmark](https://paste.divy.work/p/-gq8Ark.js):
```
$ deno run -A bench.mjs # main (568dd)
existsSync: 8980.636629ms

$ target/release/deno run -A bench.mjs # this PR
existsSync: 6448.7604519999995ms

$ bun bench.mjs
existsSync: 6562.88671ms

$ node bench.mjs
existsSync: 7740.064653ms
```

Ref https://github.com/denoland/deno/pull/24434#discussion_r1679777912
2024-07-17 18:05:51 +05:30

41 lines
1.5 KiB
TypeScript

// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
// TODO(petamoriken): enable prefer-primordials for node polyfills
// deno-lint-ignore-file prefer-primordials
import { op_node_fs_exists, op_node_fs_exists_sync } from "ext:core/ops";
import { pathFromURL } from "ext:deno_web/00_infra.js";
type ExistsCallback = (exists: boolean) => void;
/**
* TODO: Also accept 'path' parameter as a Node polyfill Buffer type once these
* are implemented. See https://github.com/denoland/deno/issues/3403
* Deprecated in node api
*/
export function exists(path: string | URL, callback: ExistsCallback) {
path = path instanceof URL ? pathFromURL(path) : path;
op_node_fs_exists(path).then(callback);
}
// The callback of fs.exists doesn't have standard callback signature.
// We need to provide special implementation for promisify.
// See https://github.com/nodejs/node/pull/13316
const kCustomPromisifiedSymbol = Symbol.for("nodejs.util.promisify.custom");
Object.defineProperty(exists, kCustomPromisifiedSymbol, {
value: (path: string | URL) => {
return new Promise((resolve) => {
exists(path, (exists) => resolve(exists));
});
},
});
/**
* TODO: Also accept 'path' parameter as a Node polyfill Buffer or URL type once these
* are implemented. See https://github.com/denoland/deno/issues/3403
*/
export function existsSync(path: string | URL): boolean {
path = path instanceof URL ? pathFromURL(path) : path;
return op_node_fs_exists_sync(path);
}