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denoland-deno/ext/node/polyfills/_fs/_fs_exists.ts
Bartek Iwańczuk b40086fd7d
refactor(core): include_js_files! 'dir' option doesn't change specifiers (#18019)
This commit changes "include_js_files!" macro from "deno_core"
in a way that "dir" option doesn't cause specifiers to be rewritten 
to include it.

Example:
```
include_js_files! {
  dir "js",
  "hello.js",
}
```

The above definition required embedders to use:
`import ... from "internal:<ext_name>/js/hello.js"`. 
But with this change, the "js" directory in which the files are stored
is an implementation detail, which for embedders results in: 
`import ... from "internal:<ext_name>/hello.js"`.

The directory the files are stored in, is an implementation detail and 
in some cases might result in a significant size difference for the 
snapshot. As an example, in "deno_node" extension, we store the 
source code in "polyfills" directory; which resulted in each specifier 
to look like "internal:deno_node/polyfills/<module_name>", but with 
this change it's "internal:deno_node/<module_name>". 

Given that "deno_node" has over 100 files, many of them having 
several import specifiers to the same extension, this change removes
10 characters from each import specifier.
2023-03-05 02:31:38 +00:00

40 lines
1.4 KiB
TypeScript

// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
import { fromFileUrl } from "internal:deno_node/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;
}
}