狀態轉換

State 表示卡片目前所處的 FSRS 學習階段。透過 scheduler.newCard() 建立的卡片初始狀態為 New。每次複習時，DefaultScheduler 會結合 FSRS 模型結果與學習步驟策略，決定下一個狀態和到期時間。

DefaultScheduler 狀態轉換流程圖

圖表按顯式步驟和間隔中介軟體處理後的最終排程間隔分類。評分會影響間隔，但不能單獨決定下一個狀態。

graduatingInterval（預設 1，單位為天）是卡片處於 Review 時的最短間隔。最終間隔短於 graduatingInterval 時進入或維持 Learning/Relearning；達到 graduatingInterval 時進入 Review。步驟被停用或為空、由模型提供間隔時，也適用這項規則。

有一個例外：Again 使用模型間隔覆蓋顯式步驟時，即使最終間隔達到 graduatingInterval，卡片仍維持 Learning/Relearning。流程圖呈現的是一般的間隔對應規則，此例外優先於圖中的規則。

零時長步驟（如 0m，或按秒四捨五入後為零的時長）視為沒有步驟，不支援負數時長。

四種狀態

狀態	含義	預設佇列
`New`	卡片是新卡，或已透過 `scheduler.forget()` 重設。	`new`
`Learning`	卡片處於初始學習階段，需要再次複習，間隔通常短於 `graduatingInterval`。	`learning`
`Review`	卡片不處於短期學習階段，間隔至少為 `graduatingInterval`。	`review`
`Relearning`	已複習過的卡片正在重新學習，需要再次複習，間隔通常短於 `graduatingInterval`。	`learning`

評分如何改變狀態

評分首先決定是否使用顯式步驟間隔。下表假設 enableShortTerm: true，且目前狀態使用的步驟列表非空：New/Learning 使用 learningSteps，Review/Relearning 使用 relearningSteps。如果該列表為空，即使另一列表設定了步驟，排程器也使用模型間隔而不套用畢業下限。

下文的畢業行為假設 maximumInterval >= graduatingInterval，且沒有其他中介軟體將間隔縮短到 graduatingInterval 以下。

評分	`New` / `Learning` / `Relearning`	`Review`
`Again`	回到第一個步驟，`learningStep` 重設為 `0`。	使用第一個重新學習步驟，`learningStep` 重設為 `0`。
`Hard`	保持目前 `learningStep`，使用 Hard 步驟間隔。	使用模型間隔，但不短於 `graduatingInterval`；維持 `Review`。
`Good`	存在下一步時推進；否則畢業進入 `Review`，使用模型間隔，但不短於 `graduatingInterval`。	使用模型間隔，但不短於 `graduatingInterval`；維持 `Review`。
`Easy`	跳過顯式步驟，畢業進入 `Review`，使用模型間隔，但不短於 `graduatingInterval`。	使用模型間隔，但不短於 `graduatingInterval`；維持 `Review`。

Hard 步驟間隔為前兩個步驟時長的平均值；只有一個步驟時，為該步驟時長的 1.5 倍。步驟為空或 enableShortTerm: false 時，所有評分都使用模型間隔，只適用下方的狀態映射。learningStep 只在卡片留在 Learning/Relearning 時保留下一步驟，卡片進入 Review 時重設為 0。

開啟 allowModelOverride（DefaultScheduler 對 FSRS-7 預設開啟）時，如果模型間隔比目前步驟長，排程器改用模型間隔。Again 的模型間隔不超過 graduatingInterval，使用模型間隔的 Again 總是進入 Learning/Relearning。Hard 和 Good 的間隔達到 graduatingInterval 時，卡片不必走完剩餘步驟即畢業進入 Review。模型間隔仍可能被其他間隔中介軟體調整。

如果 maximumInterval < graduatingInterval，上限可能阻止畢業。例如，設定 graduatingInterval: 2 和 maximumInterval: 1 時，走完學習步驟後的模型間隔被限制為 1 天，因此卡片仍處於 Learning。

間隔確定後，schedulerLearningStepsMiddleware 按下表決定狀態。上文的 Again 模型覆蓋例外優先於此表。下表描述狀態轉換，不代表各評分使用相同的間隔選擇規則：

目前狀態	最終間隔 < `graduatingInterval`	最終間隔 ≥ `graduatingInterval`
`New`	`Learning`	`Review`
`Learning`	`Learning`	`Review`
`Review`	`Relearning`	`Review`
`Relearning`	`Relearning`	`Review`

有適用的顯式步驟時，排程器保留該步驟設定的時長，除非 allowModelOverride 選用了較長的模型間隔。達到 graduatingInterval 的步驟仍會讓卡片進入 Review。

Learning 狀態依賴中介軟體

DefaultScheduler 自動註冊 schedulerLearningStepsMiddleware，且 enableShortTerm 預設為 true，FSRS-7 也一樣。對於 FSRS-7，此開關控制顯式 learningSteps 和 relearningSteps，不關閉模型內在的短期記憶，也不控制依間隔進行的狀態映射。即使 enableShortTerm: false，模型間隔小於 graduatingInterval 時仍會進入 Learning 或 Relearning。使用 defineScheduler 時，需註冊 .use(schedulerLearningStepsMiddleware) 才會套用此狀態映射；只組合 FSRS-7 模型而未註冊此中介軟體時，即使排程間隔小於一天，state 仍為 Review，scheduleStatus 仍為 review。模型負責記憶狀態和間隔計算，學習狀態轉換由中介軟體負責。如果要讓 FSRS-7 排程後顯示 Learning/Relearning，請掛載 schedulerLearningStepsMiddleware，或自行實作負責狀態轉換的 middleware。

Rating.Manual 不是複習評分。呼叫 review() 時應傳入 Again、Hard、Good 或 Easy。

執行狀態轉換

下方的可執行範例使用預設 FSRS-7 模型和以下設定：

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

graduatingInterval 使用預設值 1 天。卡片初始狀態為 New，learningStep: 0。learningStep 是從零開始的步驟索引，不是複習次數；學習和重新學習都使用同一個欄位記錄步驟進度。

設定 allowModelOverride: false 時，範例產生以下轉換：

目前狀態	目前 learningStep	評分	轉換後狀態	轉換後 learningStep	間隔
New	0	Again	Learning	0	1 分鐘
Learning	0	Good	Learning	1	10 分鐘
Learning	1	Hard	Learning	1	5.5 分鐘
Learning	1	Again	Learning	0	1 分鐘
Learning	1	Good	Review	0	1 天
Review	0	Again	Relearning	0	10 分鐘
Relearning	0	Good	Review	0	1 天

learningStep: 1 的 Hard、Again 和 Good 行是對同一張卡片的不同評分分支，並非連續複習。重新學習分支從另一張透過 Easy 進入 Review 的卡片開始。

關閉 allowModelOverride 會保留設定的步驟間隔。開啟後，較長的模型間隔可以取代顯式步驟。例如，假設模型間隔為 30 分鐘，原本 10 分鐘的 Good 步驟就會延長到 30 分鐘；如果模型間隔較短，則該步驟維持不變。即使設定 allowModelOverride: false，排程器在步驟完成後或沒有適用步驟時仍會使用模型間隔。

下方完整範例使用公開的 DefaultSchedulerCard、Grade 和 State 型別，輸出間隔以分鐘顯示，保留兩位小數。

dueAt 不是 now

dueAt 表示卡片應從何時起複習，now 是實際複習時間，通常應滿足 now >= dueAt。為了讓輸出可以重複驗證且不混淆兩者，本例會在每張卡片的 dueAt 後 30 秒進行複習。

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 與記憶狀態

輸入 card 表示複習前的狀態；review() 不會修改它。
result.card 包含下一個 state、下一組 FSRS 記憶狀態（FSRS-7 的 stability、stabilityFast 與 difficulty）以及新的 dueAt。
result.revlog 會連同評分和複習時間記錄先前的狀態與記憶狀態；rollback 也使用這份快照還原卡片。
scheduleStatus 決定卡片進入哪個排程佇列。預設情況下，New 對應 new，兩個學習狀態對應 learning，Review 對應 review；middleware 可以加入 suspended 等佇列狀態，而不會改變四種 FSRS 狀態。

用 card.state 解釋學習階段，用 card.scheduleStatus 篩選排程佇列。

#狀態轉換

#四種狀態

#評分如何改變狀態

#執行狀態轉換

#Card、revlog 與記憶狀態

狀態轉換

四種狀態

評分如何改變狀態

執行狀態轉換

Card、revlog 與記憶狀態