> For AI agents: the complete documentation index is available at https://open-spaced-repetition.github.io/ts-fsrs/ja-JP/llms.txt, the full documentation bundle is available at https://open-spaced-repetition.github.io/ts-fsrs/ja-JP/llms-full.txt. # ts-fsrs 6.0.0 Published: 2026-10-28 14:10:26 UTC
[npmx](https://npmx.dev/package/ts-fsrs/v/6.0.0) ยท [GitHub Release](https://github.com/open-spaced-repetition/ts-fsrs/releases/tag/v6.0.0)
[All updates](https://open-spaced-repetition.github.io/ts-fsrs/ja-JP/updates/index.md) This is a major update with breaking changes. ts-fsrs v6 introduces FSRS-7, the default model for `DefaultScheduler`; see the [quick start](https://open-spaced-repetition.github.io/ts-fsrs/guide/quick-start#start-with-defaultscheduler) to get started. For existing integrations, we recommend following the [migration guide](https://open-spaced-repetition.github.io/ts-fsrs/guide/migration) and using [llms.txt](https://open-spaced-repetition.github.io/ts-fsrs/llms.txt) as the documentation entry point for AI-assisted migration. ### Breaking Changes - Change `FSRSVersion` from `v${version} using FSRS-6.0` to `v${version}`. This export remains supported and reports only the package version; update code that parses the old suffix. Read the selected model name from `scheduler.definition.model.name`. ([#576](https://github.com/open-spaced-repetition/ts-fsrs/pull/576)) Thanks [@ishiko732](https://github.com/ishiko732)! - Move algorithm operations to explicit model entries. Import models and parameter helpers from `ts-fsrs/models/fsrs-3`, `fsrs-4`, `fsrs-4dot5`, `fsrs-5`, `fsrs-6`, or `fsrs-7`. The root `FSRSAlgorithm`, `computeDecayFactor`, `clipParameters`, `migrateParameters`, and `forgetting_curve` exports and the legacy facade's `next_state`, `next_interval`, and `get_retrievability` methods are removed. The inherited algorithm API, including `interval_modifier`, `calculate_interval_modifier`, `apply_fuzz`, and the `seed` setter, is no longer available on `FSRS`. Use model `step`, `nextInterval`, `forgettingCurve`, and `forward`; `retrievability` returns a number, so format percentages at the call site. `FSRS`, `IFSRS`, and `fsrs()` remain exported but deprecated and use FSRS-6. ([#377](https://github.com/open-spaced-repetition/ts-fsrs/pull/377), [#375](https://github.com/open-spaced-repetition/ts-fsrs/pull/375), [#356](https://github.com/open-spaced-repetition/ts-fsrs/pull/356)) Thanks [@ishiko732](https://github.com/ishiko732)! - Remove `afterHandler` callbacks from `createEmptyCard`, `repeat`, `next`, `rollback`, and `forget`, and remove `recordLogHandler` from legacy `reschedule`. Transform returned results at the call site. ([#374](https://github.com/open-spaced-repetition/ts-fsrs/pull/374)) Thanks [@ishiko732](https://github.com/ishiko732) and [@Copilot](https://github.com/Copilot)! - Remove global `Date.prototype` extensions and deprecated `fixDate`, `fixState`, and `fixRating` helpers. Use standalone date helpers and `TypeConvert.time/state/rating` for legacy integrations. Remove `Card.elapsed_days` and `ReviewLog.elapsed_days/last_elapsed_days`; derive elapsed time from actual review timestamps, not the scheduled due date. ([#341](https://github.com/open-spaced-repetition/ts-fsrs/pull/341), [#342](https://github.com/open-spaced-repetition/ts-fsrs/pull/342)) Thanks [@ishiko732](https://github.com/ishiko732)! - Replace Alea with FNV-1a and Mulberry32, changing fuzzed interval sequences. The new scheduler seeds fuzzing with `cardId + reps`; the legacy scheduler still derives its seed from review time, repetition count, difficulty, and stability. Remove `DefaultInitSeedStrategy`, `GenSeedStrategyWithCardId`, `StrategyMode.SEED`, and `TSeedStrategy`. Use `schedulerFuzzingMiddleware` or `createSchedulerFuzzingMiddleware({ fuzzingRange, rng })`. ([#409](https://github.com/open-spaced-repetition/ts-fsrs/pull/409)) Thanks [@ishiko732](https://github.com/ishiko732)! - Require Node.js 24 or later. ([#406](https://github.com/open-spaced-repetition/ts-fsrs/pull/406)) Thanks [@ishiko732](https://github.com/ishiko732)! - Replace `BasicLearningStepsStrategy` with `calculateLearningSteps` and `TLearningStepsStrategy` with `LearningStepsResolver`. Custom `StrategyMode.LEARNING_STEPS` handlers now receive camelCase `learningSteps`/`relearningSteps` config and return `scheduledMinutes`/`nextStep` instead of `scheduled_minutes`/`next_step`. Replace `default_learning_steps` and `default_relearning_steps` imports with `defaultLearningSteps` and `defaultRelearningSteps`. ([#407](https://github.com/open-spaced-repetition/ts-fsrs/pull/407)) Thanks [@ishiko732](https://github.com/ishiko732)! - Replace the numeric TypeScript enums `Rating` and `State` with frozen constant objects and numeric union types. Numeric values remain unchanged, but reverse lookups such as `Rating[3]` and `State[2]` no longer work; replace enum-member type annotations such as `Rating.Good` with `typeof Rating.Good`. ([#457](https://github.com/open-spaced-repetition/ts-fsrs/pull/457)) Thanks [@ishiko732](https://github.com/ishiko732)! - Rename `FSRSReview.delta_t` to `deltaT` and narrow its `rating` to `Grade` (Again through Easy, excluding Manual). Custom legacy schedulers now receive `(card, now, model, parameters, strategies)` instead of `(card, now, algorithm, strategies)`; subclasses must use the model and separate parameters rather than `this.algorithm`. ([#377](https://github.com/open-spaced-repetition/ts-fsrs/pull/377)) Thanks [@ishiko732](https://github.com/ishiko732)! - Change declaration files from `dist/index.d.ts` to format-specific `.d.mts`/`.d.cts` files and remove the `umd` package-export condition. Use package imports for declaration resolution and update tooling that hard-codes the old declaration path; the UMD bundle is still built. ([#346](https://github.com/open-spaced-repetition/ts-fsrs/pull/346)) Thanks [@ishiko732](https://github.com/ishiko732)! ### Deprecations - Add explicit `@deprecated` annotations and replacement guidance to legacy card/parameter helpers, `AbstractScheduler`, strategy APIs, `FSRS`/`IFSRS` members, and legacy card, review-log, config, and scheduling types. These exports remain available for compatibility. Use `DefaultScheduler` or `defineScheduler`, model-specific parameter helpers, inferred scheduler types, and `Reschedule` from `ts-fsrs/reschedule` for new integrations. ([#576](https://github.com/open-spaced-repetition/ts-fsrs/pull/576)) Thanks [@ishiko732](https://github.com/ishiko732)! - Deprecate `TypeConvert` and its methods, legacy date helpers, `Grades`, and `CLAMP_PARAMETERS`. Use explicit input conversion and schemas, the selected scheduler's chrono, application-level date formatting, `grades` from srs-kit, and model-specific parameter helpers. Replacements are not universally interchangeable: preserve date units, rounding, output formats, and the New-card retrievability boundary when migrating. ([#576](https://github.com/open-spaced-repetition/ts-fsrs/pull/576)) Thanks [@ishiko732](https://github.com/ishiko732)! ### New Features - Add the asynchronous `DefaultScheduler(options)` factory backed by `@open-spaced-repetition/srs-kit`. It defaults to FSRS-7; select `version: 'FSRS-6'` to retain the previous model. The new API uses `newCard`, `preview`, `review`, `rollback`, `forget`, `retrievability`, and `nextInterval`, with camelCase card/config fields and `{ card, revlog }` review results. ([#451](https://github.com/open-spaced-repetition/ts-fsrs/pull/451), [#531](https://github.com/open-spaced-repetition/ts-fsrs/pull/531), [#526](https://github.com/open-spaced-repetition/ts-fsrs/pull/526)) Thanks [@ishiko732](https://github.com/ishiko732)! - Add FSRS-3, FSRS-4, FSRS-4.5, FSRS-5, and FSRS-7 model entries alongside FSRS-6. FSRS-7 uses 34 weights, a `stabilityFast` memory field, and fractional-day intervals. Its standalone `curve` returns retrievability and total mixture weight; parameter bounds are also exported. ([#401](https://github.com/open-spaced-repetition/ts-fsrs/pull/401), [#400](https://github.com/open-spaced-repetition/ts-fsrs/pull/400), [#399](https://github.com/open-spaced-repetition/ts-fsrs/pull/399), [#378](https://github.com/open-spaced-repetition/ts-fsrs/pull/378), [#520](https://github.com/open-spaced-repetition/ts-fsrs/pull/520), [#541](https://github.com/open-spaced-repetition/ts-fsrs/pull/541), [#556](https://github.com/open-spaced-repetition/ts-fsrs/pull/556)) Thanks [@ishiko732](https://github.com/ishiko732)! - Expose `defineModel`, `defineScheduler`, `defineChrono`, `defineMiddleware`, chrono presets, scheduling schemas, and srs-kit types for custom integrations. Built-in middleware is available from the root and `ts-fsrs/middlewares`, including desired retention, fuzzing, statistics, scheduled days, learning steps, maximum/monotonic intervals, leech suspension, and Cost ADR. Leech suspension uses `scheduleStatus: 'suspended'`; Cost ADR and leech middleware are opt-in. ([#445](https://github.com/open-spaced-repetition/ts-fsrs/pull/445), [#469](https://github.com/open-spaced-repetition/ts-fsrs/pull/469), [#509](https://github.com/open-spaced-repetition/ts-fsrs/pull/509), [#539](https://github.com/open-spaced-repetition/ts-fsrs/pull/539), [#412](https://github.com/open-spaced-repetition/ts-fsrs/pull/412), [#461](https://github.com/open-spaced-repetition/ts-fsrs/pull/461), [#528](https://github.com/open-spaced-repetition/ts-fsrs/pull/528)) Thanks [@ishiko732](https://github.com/ishiko732)! - Support per-grade desired retention and direct `nextInterval` queries through interval middleware. Add `graduatingInterval` and `allowModelOverride` to learning-step scheduling. `DefaultScheduler` defaults to learning steps `['1m', '10m']`, relearning steps `['10m']`, and model override enabled only for FSRS-7. Disabling explicit learning steps does not disable FSRS-7's intrinsic fast trace. ([#527](https://github.com/open-spaced-repetition/ts-fsrs/pull/527), [#526](https://github.com/open-spaced-repetition/ts-fsrs/pull/526), [#561](https://github.com/open-spaced-repetition/ts-fsrs/pull/561)) Thanks [@ishiko732](https://github.com/ishiko732)! - Add `Reschedule` at `ts-fsrs/reschedule` for replaying review history into memory states or rescheduling cards and review logs. ([#426](https://github.com/open-spaced-repetition/ts-fsrs/pull/426), [#439](https://github.com/open-spaced-repetition/ts-fsrs/pull/439)) Thanks [@ishiko732](https://github.com/ishiko732) and [@Eijnewgnaw](https://github.com/Eijnewgnaw)! - Separate parameter migration, clipping, and validation, and accept readonly parameter arrays. ([#398](https://github.com/open-spaced-repetition/ts-fsrs/pull/398), [#492](https://github.com/open-spaced-repetition/ts-fsrs/pull/492), [#515](https://github.com/open-spaced-repetition/ts-fsrs/pull/515)) Thanks [@ishiko732](https://github.com/ishiko732) and [@Luc-Mcgrady](https://github.com/Luc-Mcgrady)! ### Fixes - Enforce maximum intervals independently of fuzzing, preserve explicit learning steps and second precision, and keep graduation intervals monotonic. Correct FSRS-7 sub-day scheduling states. ([#454](https://github.com/open-spaced-repetition/ts-fsrs/pull/454), [#456](https://github.com/open-spaced-repetition/ts-fsrs/pull/456), [#484](https://github.com/open-spaced-repetition/ts-fsrs/pull/484), [#540](https://github.com/open-spaced-repetition/ts-fsrs/pull/540)) Thanks [@ishiko732](https://github.com/ishiko732)! - Clamp FSRS-4.5 through FSRS-6 initial stability to configured bounds, and validate numeric bounds and learning-step inputs. ([#477](https://github.com/open-spaced-repetition/ts-fsrs/pull/477), [#549](https://github.com/open-spaced-repetition/ts-fsrs/pull/549)) Thanks [@ishiko732](https://github.com/ishiko732)! - Preserve pre-review chronology during rollback, improve inferred card/revlog type displays, and avoid redundant interval calculations. ([#522](https://github.com/open-spaced-repetition/ts-fsrs/pull/522), [#473](https://github.com/open-spaced-repetition/ts-fsrs/pull/473), [#443](https://github.com/open-spaced-repetition/ts-fsrs/pull/443)) Thanks [@ishiko732](https://github.com/ishiko732)! ### Build and Tooling - Replace Rollup/esbuild with tsdown (Rolldown), and stop emitting source maps and minified bundles. ([#346](https://github.com/open-spaced-repetition/ts-fsrs/pull/346)) Thanks [@ishiko732](https://github.com/ishiko732)! - Add the build-time `TS_FSRS_DISABLE_ROUNDING` switch for custom builds. Published builds keep rounding enabled; this is not a runtime environment setting. ([#547](https://github.com/open-spaced-repetition/ts-fsrs/pull/547)) Thanks [@ishiko732](https://github.com/ishiko732)! - Migrate the repository's root TypeScript toolchain to TypeScript 7 (tsgo). `srs-kit` retains its package-local TypeScript 6 development dependency. This is a development-toolchain change, not a new TypeScript 7 requirement for consumers. ([#403](https://github.com/open-spaced-repetition/ts-fsrs/pull/403)) Thanks [@zi-gae](https://github.com/zi-gae)! ### Migration Upgrading the package and upgrading the model are separate operations. Keep FSRS-6 explicitly when migrating an existing FSRS-6 integration. To move learned cards to FSRS-7, use FSRS-7 weights and rebuild memory from complete review history since creation or the latest memory reset; do not reuse FSRS-6 weights or invent `stabilityFast`. Select the post-reset history explicitly: `replay()` filters Manual records but does not interpret reset events. Use `Reschedule.replay()` to rebuild memory while preserving existing due dates, learning progress, counters, and historical logs; `reschedule()` instead replays scheduling policy and can change the schedule. The new scheduler's `forget` clears statistics by default; set `clearStatsOnForget: false` when those statistics must be retained. When adopting the new scheduler, migrate `due`/`last_review` to `dueAt`/`lastReviewAt`, `learning_steps` to `learningStep`, and `{ card, log }` to `{ card, revlog }`; persist `scheduleStatus` and retain a stable `cardId`. Date-based inputs require valid `Date` objects after deserialization. Review logs distinguish the pre-review `lastReviewAt`, pre-review `dueAt`, and actual `reviewTime`; do not blindly rename old `log.due` or use old-model logs for FSRS-7 rollback. Learned cards without complete history must remain on FSRS-6 rather than receiving an invented FSRS-7 state. See the [v6 and FSRS-7 migration guide](https://open-spaced-repetition.github.io/ts-fsrs/guide/migration) for card/config mappings and rollback timestamp requirements. ([#543](https://github.com/open-spaced-repetition/ts-fsrs/pull/543)) Thanks [@ishiko732](https://github.com/ishiko732)!