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denoland-deno/ext/node/polyfills/_fs/_fs_exists.ts
Bartek Iwańczuk d47147fb6a
feat(ext/node): embed std/node into the snapshot (#17724)
This commit moves "deno_std/node" in "ext/node" crate. The code is
transpiled and snapshotted during the build process.

During the first pass a minimal amount of work was done to create the
snapshot, a lot of code in "ext/node" depends on presence of "Deno"
global. This code will be gradually fixed in the follow up PRs to migrate
it to import relevant APIs from "internal:" modules.

Currently the code from snapshot is not used in any way, and all
Node/npm compatibility still uses code from 
"https://deno.land/std/node" (or from the location specified by 
"DENO_NODE_COMPAT_URL"). This will also be handled in a follow 
up PRs.

---------

Co-authored-by: crowlkats <crowlkats@toaxl.com>
Co-authored-by: Divy Srivastava <dj.srivastava23@gmail.com>
Co-authored-by: Yoshiya Hinosawa <stibium121@gmail.com>
2023-02-14 17:38:45 +01:00

40 lines
1.4 KiB
TypeScript

// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
import { fromFileUrl } from "internal:deno_node/polyfills/path.ts";
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 ? fromFileUrl(path) : path;
Deno.lstat(path).then(() => callback(true), () => callback(false));
}
// 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 ? fromFileUrl(path) : path;
try {
Deno.lstatSync(path);
return true;
} catch (_err) {
return false;
}
}