Introduction | 简体中文 ｜はじめに

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ts-fsrs

ts-fsrs is a TypeScript toolkit for building spaced repetition systems with FSRS.

Packages

This repository contains two main packages:

Package	Description	FSRS Version	Package Version	Downloads
ts-fsrs	the scheduler for review flows
@open-spaced-repetition/binding	the optimizer for parameter training and CSV conversion

Installation

All current packages in this repository require Node.js >=20.0.0.

Node.js 16 and 18 are end-of-life, so we no longer support versions earlier than Node.js 20. See the official release status page.

pnpm add ts-fsrs

If you also need parameter optimization from review logs:

pnpm add @open-spaced-repetition/binding

Basic Usage

Use ts-fsrs to schedule reviews:

import { createEmptyCard, fsrs, Rating } from 'ts-fsrs'

const scheduler = fsrs()
const card = createEmptyCard()

// Preview all four possible outcomes before the user answers.
const preview = scheduler.repeat(card, new Date())
// Apply the final rating after the user has already answered.
const result = scheduler.next(card, new Date(), Rating.Good)

console.log(preview[Rating.Good].card)
console.log(result.card)
console.log(result.log)

Use @open-spaced-repetition/binding when you want to train FSRS parameters from review logs. For CSV conversion, timezone handling, browser/WASI setup, and training examples, see packages/binding/README.md.

More Documentation

For detailed usage, advanced examples, browser/WASI setup, and API notes:

• packages/fsrs/README.md
• packages/binding/README.md
• TypeDoc API docs
• State transition diagram for cards

Examples

• ts-fsrs package examples
• @open-spaced-repetition/binding package examples

Other Implementations

FSRS is also available in other languages and ecosystems:

• awesome-fsrs implementations

Contribute

For how to setup a local development eniroment, how to set up a Dev Container, and contribution guidelines, see CONTRIBUTING.md.