状态转换

State 表示卡片当前所处的 FSRS 学习阶段。通过 scheduler.newCard() 创建的卡片初始状态为 New。每次复习时，DefaultScheduler 会结合 FSRS 模型结果与学习步骤策略，确定下一个状态和到期时间。

DefaultScheduler 状态转换流程图

图表按显式步骤和间隔中间件处理后的最终调度间隔分类。评分会影响间隔，但不能单独决定下一个状态。

graduatingInterval（默认 1，单位为天）是卡片处于 Review 时的最短间隔。最终间隔短于 graduatingInterval 时进入或保持 Learning/Relearning；达到 graduatingInterval 时进入 Review。步骤被关闭或为空、由模型提供间隔时，也适用这一规则。

有一个例外：Again 使用模型间隔覆盖显式步骤时，即使最终间隔达到 graduatingInterval，卡片仍保持 Learning/Relearning。流程图展示的是一般的间隔映射规则，此例外优先于图中的规则。

零时长步骤（如 0m，或按秒四舍五入后为零的时长）视为没有步骤，不支持负数时长。

四种状态

状态	含义	默认队列
`New`	卡片是新卡，或已通过 `scheduler.forget()` 重置。	`new`
`Learning`	卡片处于初始学习阶段，需要再次复习，间隔通常短于 `graduatingInterval`。	`learning`
`Review`	卡片不处于短期学习阶段，间隔至少为 `graduatingInterval`。	`review`
`Relearning`	已复习过的卡片正在重新学习，需要再次复习，间隔通常短于 `graduatingInterval`。	`learning`

评分如何改变状态

评分首先决定是否使用显式步骤间隔。下表假设 enableShortTerm: true，且当前状态使用的步骤列表非空：New/Learning 使用 learningSteps，Review/Relearning 使用 relearningSteps。如果该列表为空，即使另一列表配置了步骤，调度器也使用模型间隔而不应用毕业下限。

下文的毕业行为假设 maximumInterval >= graduatingInterval，且没有其他中间件将间隔缩短到 graduatingInterval 以下。

评分	`New` / `Learning` / `Relearning`	`Review`
`Again`	回到第一个步骤，`learningStep` 重置为 `0`。	使用第一个重新学习步骤，`learningStep` 重置为 `0`。
`Hard`	保持当前 `learningStep`，使用 Hard 步骤间隔。	使用模型间隔，但不短于 `graduatingInterval`；保持 `Review`。
`Good`	存在下一步时推进；否则毕业进入 `Review`，使用模型间隔，但不短于 `graduatingInterval`。	使用模型间隔，但不短于 `graduatingInterval`；保持 `Review`。
`Easy`	跳过显式步骤，毕业进入 `Review`，使用模型间隔，但不短于 `graduatingInterval`。	使用模型间隔，但不短于 `graduatingInterval`；保持 `Review`。

Hard 步骤间隔为前两个步骤时长的平均值；只有一个步骤时，为该步骤时长的 1.5 倍。步骤为空或 enableShortTerm: false 时，所有评分都使用模型间隔，只适用下方的状态映射。learningStep 只在卡片留在 Learning/Relearning 时保留下一步骤，卡片进入 Review 时重置为 0。

开启 allowModelOverride（DefaultScheduler 对 FSRS-7 默认开启）时，如果模型间隔比当前步骤长，调度器改用模型间隔。Again 的模型间隔不超过 graduatingInterval，使用模型间隔的 Again 总是进入 Learning/Relearning。Hard 和 Good 的间隔达到 graduatingInterval 时，卡片不必走完剩余步骤即毕业进入 Review。模型间隔仍可能被其他间隔中间件调整。

如果 maximumInterval < graduatingInterval，上限可能阻止毕业。例如，设置 graduatingInterval: 2 和 maximumInterval: 1 时，走完学习步骤后的模型间隔被限制为 1 天，因此卡片仍处于 Learning。

间隔确定后，schedulerLearningStepsMiddleware 按下表决定状态。上文的 Again 模型覆盖例外优先于此表。下表描述状态转换，不代表各评分使用相同的间隔选择规则：

当前状态	最终间隔 < `graduatingInterval`	最终间隔 ≥ `graduatingInterval`
`New`	`Learning`	`Review`
`Learning`	`Learning`	`Review`
`Review`	`Relearning`	`Review`
`Relearning`	`Relearning`	`Review`

有适用的显式步骤时，调度器保留该步骤配置的时长，除非 allowModelOverride 选用了更长的模型间隔。达到 graduatingInterval 的步骤仍会让卡片进入 Review。

Learning 状态依赖中间件

DefaultScheduler 自动注册 schedulerLearningStepsMiddleware，且 enableShortTerm 默认为 true，FSRS-7 也一样。对于 FSRS-7，该开关控制显式 learningSteps 和 relearningSteps，不关闭模型内在的短期记忆，也不控制按间隔进行的状态映射。即使 enableShortTerm: false，模型间隔小于 graduatingInterval 时仍会进入 Learning 或 Relearning。使用 defineScheduler 时，需注册 .use(schedulerLearningStepsMiddleware) 才会应用此状态映射；只组合 FSRS-7 模型而未注册该中间件时，即使调度间隔小于一天，state 仍为 Review，scheduleStatus 仍为 review。模型负责记忆状态和间隔计算，学习状态转换由中间件负责。如果要让 FSRS-7 调度后显示 Learning/Relearning，请挂载 schedulerLearningStepsMiddleware，或自行实现负责状态转换的 middleware。

Rating.Manual 不是复习评分。调用 review() 时应传入 Again、Hard、Good 或 Easy。

运行状态转换

下方的可运行示例使用默认 FSRS-7 模型和以下配置：

const scheduler = await DefaultScheduler({
  learningSteps: ['1m', '10m'],
  relearningSteps: ['10m'],
  enableFuzz: false,
  allowModelOverride: false,
})

graduatingInterval 使用默认值 1 天。卡片初始状态为 New，learningStep: 0。learningStep 是从零开始的步骤索引，不是复习次数；学习和重新学习都使用同一个字段记录步骤进度。

设置 allowModelOverride: false 时，示例产生以下转换：

当前状态	当前 learningStep	评分	转换后状态	转换后 learningStep	间隔
New	0	Again	Learning	0	1 分钟
Learning	0	Good	Learning	1	10 分钟
Learning	1	Hard	Learning	1	5.5 分钟
Learning	1	Again	Learning	0	1 分钟
Learning	1	Good	Review	0	1 天
Review	0	Again	Relearning	0	10 分钟
Relearning	0	Good	Review	0	1 天

learningStep: 1 的 Hard、Again 和 Good 行是对同一张卡片的不同评分分支，并非连续复习。重新学习分支从另一张通过 Easy 进入 Review 的卡片开始。

关闭 allowModelOverride 会保留配置的步骤间隔。开启后，更长的模型间隔可以替代显式步骤。例如，假设模型间隔为 30 分钟，原本 10 分钟的 Good 步骤就会延长到 30 分钟；如果模型间隔更短，则该步骤保持不变。即使设置 allowModelOverride: false，调度器在步骤完成后或没有适用步骤时仍会使用模型间隔。

下方完整示例使用公开的 DefaultSchedulerCard、Grade 和 State 类型，输出间隔以分钟显示，保留两位小数。

dueAt 不是 now

dueAt 表示卡片应从何时起复习，now 是实际复习时间，通常应满足 now >= dueAt。为了让输出可重复且不混淆两者，本例在每张卡片的 dueAt 后 30 秒进行复习。

import {
  function DefaultScheduler<Version extends DefaultSchedulerVersion = "FSRS-7">(options?: DefaultSchedulerOptions<Version>): Promise<DefaultScheduler<Version>>
type DefaultScheduler<Version extends DefaultSchedulerVersion = "FSRS-7"> = (Version extends "FSRS-7" ? Omit<SchedulerCore<SchedulerCoreEnv<SchedulerEnvFor<FSRS7DefaultSchedulerModel, Chrono<{
    readonly time: SRSSchema<{
        input: Date;
        output: Date;
    }>;
    readonly config: SRSSchema<{
        input: {
            readonly fractionalDays?: boolean | undefined;
        };
        output: {
            readonly fractionalDays: boolean;
        };
    }>;
    readonly fields: {
        readonly card: SRSSchema<{
            input: {
                dueAt: Date;
                lastReviewAt?: (Date | null) | undefined;
            };
            output: {
                dueAt: Date;
                lastReviewAt: Date | null;
            };
        }>;
        readonly revlog: SRSSchema<{
            input: {
                dueAt: Date;
                lastReviewAt?: (Date | null) | undefined;
                reviewTime: Date;
            };
            output: {
                dueAt: Date;
                lastReviewAt: Date | null;
                reviewTime: Date;
            };
        }>;
    };
}>, readonly [...]>>, ModelCore<...>, ChronoCore<...>>, "definition"> : Omit<...> & {
    ...;
}) & {
    ...;
}
DefaultScheduler,
  type type DefaultSchedulerCard<Version extends DefaultSchedulerVersion = "FSRS-7"> = Version extends "FSRS-7" ? {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
} : {
    cardId: string | number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
DefaultSchedulerCard,
  type type Grade = 1 | 2 | 3 | 4Grade,
  type Rating = 0 | 1 | 2 | 3 | 4
const Rating: Readonly<{
    readonly Manual: 0;
    readonly Again: 1;
    readonly Hard: 2;
    readonly Good: 3;
    readonly Easy: 4;
}>
Rating,
  type State = 0 | 1 | 2 | 3
const State: Readonly<{
    readonly New: 0;
    readonly Learning: 1;
    readonly Review: 2;
    readonly Relearning: 3;
}>
State,
} from 'ts-fsrs'

const const scheduler: DefaultScheduler<"FSRS-7">scheduler = await DefaultScheduler<"FSRS-7">(options?: DefaultSchedulerOptions<"FSRS-7"> | undefined): Promise<DefaultScheduler<"FSRS-7">>DefaultScheduler({
  DefaultSchedulerOptions<"FSRS-7">.learningSteps?: readonly (`${number}d` | `${number}m` | `${number}h`)[] | undefinedDefaults to ['1m', '10m'].learningSteps: ['1m', '10m'],
  DefaultSchedulerOptions<"FSRS-7">.relearningSteps?: readonly (`${number}d` | `${number}m` | `${number}h`)[] | undefinedDefaults to ['10m'].relearningSteps: ['10m'],
  DefaultSchedulerOptions<Version extends DefaultSchedulerVersion = DefaultSchedulerVersion>.enableFuzz?: boolean | undefinedenableFuzz: false,
  DefaultSchedulerOptions<Version extends DefaultSchedulerVersion = DefaultSchedulerVersion>.allowModelOverride?: boolean | undefinedLet longer model intervals override learning steps; defaults to true for FSRS-7 only.allowModelOverride: false,
})
const stateNames: Record<type State = 0 | 1 | 2 | 3State, string> = {
  [const State: Readonly<{
    readonly New: 0;
    readonly Learning: 1;
    readonly Review: 2;
    readonly Relearning: 3;
}>
State.New]: 'New',
  [const State: Readonly<{
    readonly New: 0;
    readonly Learning: 1;
    readonly Review: 2;
    readonly Relearning: 3;
}>
State.Learning]: 'Learning',
  [const State: Readonly<{
    readonly New: 0;
    readonly Learning: 1;
    readonly Review: 2;
    readonly Relearning: 3;
}>
State.Review]: 'Review',
  [const State: Readonly<{
    readonly New: 0;
    readonly Learning: 1;
    readonly Review: 2;
    readonly Relearning: 3;
}>
State.Relearning]: 'Relearning',
}
const const reviewAfterDue: (card: DefaultSchedulerCard, grade: Grade) => {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
reviewAfterDue = (card: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
card: type DefaultSchedulerCard<Version extends DefaultSchedulerVersion = "FSRS-7"> = Version extends "FSRS-7" ? {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
} : {
    cardId: string | number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
DefaultSchedulerCard, grade: type Grade = 1 | 2 | 3 | 4Grade) => {
  const reviewedAt = new Date(card: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
card.dueAt.getTime() + 30_000)
  return const scheduler: DefaultScheduler<"FSRS-7">scheduler.review: (input: {
    readonly card: Readonly<Omit<Readonly<{
        stabilityFast: number;
        stability: number;
        difficulty: number;
    } & {
        dueAt: Date;
        lastReviewAt: Date | null;
    } & {
        readonly cardId: string | number;
        readonly reps: number;
        readonly lapses: number;
        readonly scheduledDays: number;
        readonly learningStep?: number | undefined;
    } & SchedulerCoreFields$1<"review" | "new" | "learning">>, keyof SchedulerCoreFields$1<"review" | "new" | "learning">> & SchedulerCoreFields$1<"review" | "new" | "learning">>;
    readonly grade: Grade;
    readonly now?: Date | undefined;
}) => {
    ...;
}
review({ card, grade, now: reviewedAt }).card: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
card
}

const const newCard: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
newCard = const scheduler: DefaultScheduler<"FSRS-7">scheduler.newCard: (options?: ({
    readonly cardId?: string | number | undefined;
} & {
    readonly now?: Date | undefined;
}) | undefined) => {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
newCard({
  cardId: 'state-transitions',
  now: new Date('2026-01-01T00:00:00.000Z'),
})
const const learning: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
learning = const reviewAfterDue: (card: DefaultSchedulerCard, grade: Grade) => {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
reviewAfterDue(const newCard: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
newCard, const Rating: Readonly<{
    readonly Manual: 0;
    readonly Again: 1;
    readonly Hard: 2;
    readonly Good: 3;
    readonly Easy: 4;
}>
Rating.Again)
const const nextLearningStep: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
nextLearningStep = const reviewAfterDue: (card: DefaultSchedulerCard, grade: Grade) => {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
reviewAfterDue(const learning: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
learning, const Rating: Readonly<{
    readonly Manual: 0;
    readonly Again: 1;
    readonly Hard: 2;
    readonly Good: 3;
    readonly Easy: 4;
}>
Rating.Good)
const const afterLearningSteps: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
afterLearningSteps = const reviewAfterDue: (card: DefaultSchedulerCard, grade: Grade) => {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
reviewAfterDue(const nextLearningStep: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
nextLearningStep, const Rating: Readonly<{
    readonly Manual: 0;
    readonly Again: 1;
    readonly Hard: 2;
    readonly Good: 3;
    readonly Easy: 4;
}>
Rating.Good)
const const repeated: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
repeated = const reviewAfterDue: (card: DefaultSchedulerCard, grade: Grade) => {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
reviewAfterDue(const nextLearningStep: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
nextLearningStep, const Rating: Readonly<{
    readonly Manual: 0;
    readonly Again: 1;
    readonly Hard: 2;
    readonly Good: 3;
    readonly Easy: 4;
}>
Rating.Hard)
const const restarted: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
restarted = const reviewAfterDue: (card: DefaultSchedulerCard, grade: Grade) => {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
reviewAfterDue(const nextLearningStep: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
nextLearningStep, const Rating: Readonly<{
    readonly Manual: 0;
    readonly Again: 1;
    readonly Hard: 2;
    readonly Good: 3;
    readonly Easy: 4;
}>
Rating.Again)
const const reviewed: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
reviewed = const reviewAfterDue: (card: DefaultSchedulerCard, grade: Grade) => {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
reviewAfterDue(const newCard: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
newCard, const Rating: Readonly<{
    readonly Manual: 0;
    readonly Again: 1;
    readonly Hard: 2;
    readonly Good: 3;
    readonly Easy: 4;
}>
Rating.Easy)
const const relearning: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
relearning = const reviewAfterDue: (card: DefaultSchedulerCard, grade: Grade) => {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
reviewAfterDue(const reviewed: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
reviewed, const Rating: Readonly<{
    readonly Manual: 0;
    readonly Again: 1;
    readonly Hard: 2;
    readonly Good: 3;
    readonly Easy: 4;
}>
Rating.Again)
const const afterRelearningSteps: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
afterRelearningSteps = const reviewAfterDue: (card: DefaultSchedulerCard, grade: Grade) => {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
reviewAfterDue(const relearning: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
relearning, const Rating: Readonly<{
    readonly Manual: 0;
    readonly Again: 1;
    readonly Hard: 2;
    readonly Good: 3;
    readonly Easy: 4;
}>
Rating.Good)

for (const [const from: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
} | {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
from, rating, const to: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
to] of [
  [const newCard: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
newCard, 'Again', const learning: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
learning],
  [const learning: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
learning, 'Good', const nextLearningStep: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
nextLearningStep],
  [const nextLearningStep: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
nextLearningStep, 'Hard', const repeated: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
repeated],
  [const nextLearningStep: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
nextLearningStep, 'Again', const restarted: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
restarted],
  [const nextLearningStep: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
nextLearningStep, 'Good', const afterLearningSteps: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
afterLearningSteps],
  [const newCard: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
newCard, 'Easy', const reviewed: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
reviewed],
  [const reviewed: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
reviewed, 'Again', const relearning: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
relearning],
  [const relearning: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
relearning, 'Good', const afterRelearningSteps: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
afterRelearningSteps],
] as type const = readonly [readonly [{
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}, "Again", {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}], readonly [{
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}, "Good", {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}], ... 5 more ..., readonly [...]]
const) {
  console.log(
    `${stateNames[const from: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
} | {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
from.state]} --${rating}--> ${stateNames[const to: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
to.state]}; ` +
      `learningStep: ${const from: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
} | {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
from.learningStep} -> ${const to: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
to.learningStep}; ` +
      `interval: ${(const to: {
    cardId: string | number;
    stabilityFast: number;
    stability: number;
    difficulty: number;
    dueAt: Date;
    lastReviewAt: Date | null;
    reps: number;
    lapses: number;
    scheduledDays: number;
    learningStep: number;
    state: State;
    scheduleStatus: "review" | "new" | "learning";
}
to.scheduledDays * 1440).toFixed(2)}m`
  )
}

Card、revlog 与记忆状态

输入 card 表示复习前的状态；review() 不会修改它。
result.card 包含下一个 state、下一组 FSRS 记忆状态（FSRS-7 的 stability、stabilityFast 与 difficulty）以及新的 dueAt。
result.revlog 会连同评分和复习时间记录之前的状态与记忆状态；rollback 也使用这份快照恢复卡片。
scheduleStatus 决定卡片进入哪个调度队列。默认情况下，New 对应 new，两个学习状态对应 learning，Review 对应 review；middleware 可以增加 suspended 等队列状态，而不会改变四种 FSRS 状态。

用 card.state 解释学习阶段，用 card.scheduleStatus 筛选调度队列。

#状态转换

#四种状态

#评分如何改变状态

#运行状态转换

#Card、revlog 与记忆状态

状态转换

四种状态

评分如何改变状态

运行状态转换

Card、revlog 与记忆状态