supermemo/esm/main.js

A JavaScript/TypeScript implementation of the SuperMemo 2 (SM2) algorithm for spaced based repetition flashcards.

/**
 * Applies the SuperMemo 2 (SM-2) algorithm to update an item's learning parameters
 * based on a given recall grade.
 *
 * @param item - The current SuperMemo item containing interval, repetition, and ease factor.
 * @param grade - The grade (0-5) assigned to the recall attempt.
 * @returns The updated SuperMemo item with adjusted interval, repetition, and ease factor.
 */
export function supermemo(item, grade) {
    let nextInterval;
    let nextRepetition;
    let nextEfactor;
    if (grade >= 3) {
        if (item.repetition === 0) {
            nextInterval = 1;
            nextRepetition = 1;
        }
        else if (item.repetition === 1) {
            nextInterval = 6;
            nextRepetition = 2;
        }
        else {
            nextInterval = Math.round(item.interval * item.efactor);
            nextRepetition = item.repetition + 1;
        }
    }
    else {
        nextInterval = 1;
        nextRepetition = 0;
    }
    nextEfactor = item.efactor + (0.1 - (5 - grade) * (0.08 + (5 - grade) * 0.02));
    if (nextEfactor < 1.3)
        nextEfactor = 1.3;
    return {
        interval: nextInterval,
        repetition: nextRepetition,
        efactor: nextEfactor,
    };
}
/**
 * Default export of the SuperMemo function.
 */
export default supermemo;