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npm · #1277 most downloaded on npm
In-memory file-system with Node's fs API.
Last release 5 days ago
29 Sep 2026
Ships fairly regularly
a new release about every 2 weeks
Nearly every release is documented
notes for 57 of the last 60 stable releases
2 versions withdrawn
withdrawn after publishing
11 years old
267 releases · first in 2015
🤖 update build target and don't emit sourcemaps
feat: allow configuring the synchronous FSA worker timeout by @Firatakti in #1298
Full Changelog: v4.79.0...v4.80.0
One column per quarter.
feat: 🎸 improve FS(A) error handling by @streamich in #1297
Full Changelog: v4.78.1...v4.79.0
fix: 🐛 return correct shape from .queryPermission() by @streamich in #1295
.queryPermission() by @streamich in #1295Full Changelog: v4.78.0...v4.78.1
feat: 🎸 implement Node-compatible cp module by @streamich in #1294
cp module by @streamich in #1294Full Changelog: v4.77.0...v4.78.0
What's Changed Glob by @streamich in #1293 Full Changelog : v4.76.0...v4.77.0
.opendir() and Dir improvements by @streamich in #1292
.opendir() and Dir improvements by @streamich in #1292Full Changelog: v4.75.0...v4.76.0
feat: 🎸 improve error formatting and normalization, dedupe validators by @streamich in #1291
Full Changelog: v4.74.0...v4.75.0
feat: 🎸 improve flags validation errors by @streamich in #1290
Full Changelog: v4.73.0...v4.74.0
feat: 🎸 improve read/write path by @streamich in #1289
Full Changelog: v4.72.2...v4.73.0
fix(memfs): resolve relative streams from virtual cwd by @xianjianlf2 in #1271
Full Changelog: v4.72.1...v4.72.2
fix(fs-node): finish BYOB file stream reads at EOF by @xianjianlf2 in #1285
Full Changelog: v4.72.0...v4.72.1
feat: 🎸 improve path validation errors by @streamich in #1288
Full Changelog: v4.71.1...v4.72.0
fix(fs-node): match Node directory iteration lifecycle by @xianjianlf2 in #1284
Full Changelog: v4.71.0...v4.71.1
feat: 🎸 improve error normalization, make them more Node.js-like by @streamich in #1283
Full Changelog: v4.70.0...v4.71.0
feat: 🎸 add 40 bound on symlink resolution and improve the algorithm, apply it to all .open() calls by @streamich in #1282
.open() calls by @streamich in #1282Full Changelog: v4.69.1...v4.70.0
refactor: 💡 improve dependencies across packages by @streamich in #1281
Full Changelog: v4.69.0...v4.69.1
feat: 🎸 improve O_NOFOLLOW flag support by @streamich in #1280
O_NOFOLLOW flag support by @streamich in #1280Full Changelog: v4.68.2...v4.69.0
fix: 🐛 align O_APPEND behavior with Linux by @streamich in #1279
Full Changelog: v4.68.1...v4.68.2
fix: 🐛 .unlink() should not delete empty directories by @streamich in https://github.com/streamich/memfs/pull/1278
.unlink() should not delete empty directories by @streamich in https://github.com/streamich/memfs/pull/1278Full Changelog: https://github.com/streamich/memfs/compare/v4.68.0...v4.68.1
.unlink() should not delete empty directories by @streamich in #1278Full Changelog: v4.68.0...v4.68.1
feat: 🎸 add file birthTime support by @streamich in https://github.com/streamich/memfs/pull/1277
birthTime support by @streamich in https://github.com/streamich/memfs/pull/1277Full Changelog: https://github.com/streamich/memfs/compare/v4.67.0...v4.68.0
birthTime support by @streamich in #1277Full Changelog: v4.67.0...v4.68.0
feat: persist git-fsa directory handle by @lux-in-tenebris-lucet in https://github.com/streamich/memfs/pull/1273
Full Changelog: https://github.com/streamich/memfs/compare/v4.66.1...v4.67.0
Full Changelog: v4.66.1...v4.67.0
fix(build): embed sources in published sourcemaps by @xianjianlf2 in https://github.com/streamich/memfs/pull/1275
Full Changelog: https://github.com/streamich/memfs/compare/v4.66.0...v4.66.1
Full Changelog: v4.66.0...v4.66.1
chore: remove tslib from peerDependencies by @xianjianlf2 in https://github.com/streamich/memfs/pull/1269
Full Changelog: https://github.com/streamich/memfs/compare/v4.65.0...v4.66.0
Full Changelog: v4.65.0...v4.66.0
test(fs-node): cover FileHandle close after unlink by @xianjianlf2 in https://github.com/streamich/memfs/pull/1272
recursive flag in FsaNodeFs by @streamich in https://github.com/streamich/memfs/pull/1274Full Changelog: https://github.com/streamich/memfs/compare/v4.64.0...v4.65.0
recursive flag in FsaNodeFs by @streamich in #1274Full Changelog: v4.64.0...v4.65.0
Fsa watch bridge improvements by @streamich in https://github.com/streamich/memfs/pull/1268
Full Changelog: https://github.com/streamich/memfs/compare/v4.63.0...v4.64.0
Full Changelog: v4.63.0...v4.64.0
Node-to-FSA watcher bridge by @streamich in https://github.com/streamich/memfs/pull/1267
Full Changelog: https://github.com/streamich/memfs/compare/v4.62.0...v4.63.0
FSA-to-Node watcher bridge implementation by @streamich in https://github.com/streamich/memfs/pull/1266
Full Changelog: https://github.com/streamich/memfs/compare/v4.61.0...v4.62.0
Full Changelog: v4.61.0...v4.62.0
test: 💍 harden test to work on Windows by @streamich in https://github.com/streamich/memfs/pull/1264
FileSystemObserver implementation by @streamich in https://github.com/streamich/memfs/pull/1265Full Changelog: https://github.com/streamich/memfs/compare/v4.60.0...v4.61.0
FileSystemObserver implementation by @streamich in #1265Full Changelog: v4.60.0...v4.61.0
Full Changelog: https://github.com/streamich/memfs/compare/v4.59.0...v4.60.0
Full Changelog: https://github.com/streamich/memfs/compare/v4.59.0...v4.60.0
CoreWatcher implementation by @streamich in https://github.com/streamich/memfs/pull/1263
CoreWatcher implementation by @streamich in https://github.com/streamich/memfs/pull/1263Full Changelog: https://github.com/streamich/memfs/compare/v4.58.0...v4.59.0
feat: 🎸 add event emission to fs-core by @streamich in https://github.com/streamich/memfs/pull/1262
Full Changelog: https://github.com/streamich/memfs/compare/v4.57.8...v4.58.0
fix: clamp negative truncate length to zero (uninitialized-memory leak) by @chatman-media in https://github.com/streamich/memfs/pull/1261
Full Changelog: https://github.com/streamich/memfs/compare/v4.57.7...v4.57.8
fix: 🐛 do not allow relative paths in snapshot restoration by @streamich in https://github.com/streamich/memfs/pull/1260
Full Changelog: https://github.com/streamich/memfs/compare/v4.57.6...v4.57.7
Full Changelog: https://github.com/streamich/memfs/compare/v4.57.5...v4.57.6
Full Changelog: https://github.com/streamich/memfs/compare/v4.57.5...v4.57.6
Full Changelog: https://github.com/streamich/memfs/compare/v4.57.4...v4.57.5
Full Changelog: https://github.com/streamich/memfs/compare/v4.57.4...v4.57.5
Add structured documentation for memfs by @streamich in https://github.com/streamich/memfs/pull/1259
Full Changelog: https://github.com/streamich/memfs/compare/v4.57.3...v4.57.4
fix: uncomment cpSync and statfsSync in fsSynchronousApiList by @GoodbyeNJN in https://github.com/streamich/memfs/pull/1256
Full Changelog: https://github.com/streamich/memfs/compare/v4.57.2...v4.57.3
fix(access): ensure symlinks are followed when checking for executable flag by @boneskull in https://github.com/streamich/memfs/pull/1253
Full Changelog: https://github.com/streamich/memfs/compare/v4.57.1...v4.57.2
fix: EBADF when calling fileHandle.close() after streaming via pipeline by @Copilot in https://github.com/streamich/memfs/pull/1249
Full Changelog: https://github.com/streamich/memfs/compare/v4.57.0...v4.57.1
feat: allow injecting custom process implementation for better testability by @Copilot in https://github.com/streamich/memfs/pull/1248
process implementation for better testability by @Copilot in https://github.com/streamich/memfs/pull/1248Full Changelog: https://github.com/streamich/memfs/compare/v4.56.11...v4.57.0
fix: normalize leading ./ in relative glob patterns by @Copilot in https://github.com/streamich/memfs/pull/1243
./ in relative glob patterns by @Copilot in https://github.com/streamich/memfs/pull/1243Full Changelog: https://github.com/streamich/memfs/compare/v4.56.10...v4.56.11
Full Changelog: https://github.com/streamich/memfs/compare/v4.56.9...v4.56.10
Full Changelog: https://github.com/streamich/memfs/compare/v4.56.9...v4.56.10
Full Changelog: https://github.com/streamich/memfs/compare/v4.56.8...v4.56.9
Full Changelog: https://github.com/streamich/memfs/compare/v4.56.8...v4.56.9
Full Changelog: https://github.com/streamich/memfs/compare/v4.56.7...v4.56.8
Full Changelog: https://github.com/streamich/memfs/compare/v4.56.7...v4.56.8
Full Changelog: https://github.com/streamich/memfs/compare/v4.56.2...v4.56.7
Full Changelog: https://github.com/streamich/memfs/compare/v4.56.2...v4.56.7
Nothing published for this version
Full Changelog: https://github.com/streamich/memfs/compare/v4.54.0...v4.56.2
Full Changelog: https://github.com/streamich/memfs/compare/v4.54.0...v4.56.2
Nothing published for this version
Nothing published for this version
🎸 add locking for FSA writable handles
implement Result type and improve error handling for exists methods (f95531f), closes #1218
🐛 add deprecated Dirent.path with deprecation notice
add glob functions to API lists
sort files and folder when using toTreeSync() (673cb7a), closes #1214
🎸 improve Node buffer allocation strategy
harden flaky watchFile test by adding proper timing delays
🐛 throw EISDIR when writing over folder
handle EEXIST error when creating directories in parallel
align openAsBlob errors with Node.js behavior
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