feat(fslib): add FileHandle.readLines (#5121)

.yarn/versions/f12a955a.yml

@@ -0,0 +1,39 @@
+releases:
+  "@yarnpkg/cli": patch
+  "@yarnpkg/core": patch
+  "@yarnpkg/fslib": minor
+  "@yarnpkg/plugin-pnp": patch
+  "@yarnpkg/pnp": patch
+
+declined:
+  - "@yarnpkg/plugin-compat"
+  - "@yarnpkg/plugin-constraints"
+  - "@yarnpkg/plugin-dlx"
+  - "@yarnpkg/plugin-essentials"
+  - "@yarnpkg/plugin-exec"
+  - "@yarnpkg/plugin-file"
+  - "@yarnpkg/plugin-git"
+  - "@yarnpkg/plugin-github"
+  - "@yarnpkg/plugin-http"
+  - "@yarnpkg/plugin-init"
+  - "@yarnpkg/plugin-interactive-tools"
+  - "@yarnpkg/plugin-link"
+  - "@yarnpkg/plugin-nm"
+  - "@yarnpkg/plugin-npm"
+  - "@yarnpkg/plugin-npm-cli"
+  - "@yarnpkg/plugin-pack"
+  - "@yarnpkg/plugin-patch"
+  - "@yarnpkg/plugin-pnpm"
+  - "@yarnpkg/plugin-stage"
+  - "@yarnpkg/plugin-typescript"
+  - "@yarnpkg/plugin-version"
+  - "@yarnpkg/plugin-workspace-tools"
+  - vscode-zipfs
+  - "@yarnpkg/builder"
+  - "@yarnpkg/doctor"
+  - "@yarnpkg/extensions"
+  - "@yarnpkg/libzip"
+  - "@yarnpkg/nm"
+  - "@yarnpkg/pnpify"
+  - "@yarnpkg/sdks"
+  - "@yarnpkg/shell"

CHANGELOG.md

@@ -17,6 +17,7 @@ Yarn now accepts sponsorships! Please give a look at our [OpenCollective](https:
 ### Compatibility
 
 - Updates the PnP compatibility layer for TypeScript v4.9.4.
+- The patched filesystem now supports `FileHandle.readLines`.
 
 ## 3.3.0
 

packages/yarnpkg-fslib/sources/patchFs/FileHandle.ts

@@ -1,4 +1,5 @@
 import type {BigIntStats, ReadStream, StatOptions, Stats, WriteStream, WriteVResult} from 'fs';
+import {createInterface}                                                             from 'readline';
 
 import type {CreateReadStreamOptions, CreateWriteStreamOptions, FakeFS}              from '../FakeFS';
 import type {Path}                                                                   from '../path';
@@ -212,6 +213,13 @@ export class FileHandle<P extends Path> {
     }
   }
 
+  readLines(options?: CreateReadStreamOptions) {
+    return createInterface({
+      input: this.createReadStream(options),
+      crlfDelay: Infinity,
+    });
+  }
+
   stat(
     opts?: StatOptions & {
       bigint?: false | undefined;

packages/yarnpkg-fslib/tests/patchedFs.test.ts

@@ -557,6 +557,25 @@ describe(`patchedFs`, () => {
     });
   });
 
+  it(`should support FileHandle.readLines`, async () => {
+    const patchedFs = extendFs(fs, new PosixFS(new NodeFS()));
+
+    await xfs.mktempPromise(async dir => {
+      const filepath = npath.join(npath.fromPortablePath(dir), `foo.txt`);
+      await patchedFs.promises.writeFile(filepath, `1\n\n2\n`);
+
+      // @ts-expect-error - Types are out of date
+      const fd = await patchedFs.promises.open(filepath);
+
+      const lines: Array<string> = [];
+      // @ts-expect-error - Types are out of date
+      for await (const line of fd.readLines())
+        lines.push(line);
+
+      expect(lines).toStrictEqual([`1`, ``, `2`]);
+    });
+  });
+
   ifNotWin32It(`should support FileHandle.chmod`, async () => {
     const patchedFs = extendFs(fs, new PosixFS(new NodeFS()));