WaniKani Answer Checker

Modifiable answer checker in reviews and lessons

This script should not be not be installed directly. It is a library for other scripts to include with the meta directive // @require https://update.greasyfork.org/scripts/470201/1215595/WaniKani%20Answer%20Checker.js

Ask a question, post a review, or report the script.

Wrap lines

// ==UserScript==
// @name         WaniKani Answer Checker
// @namespace    http://www.wanikani.com
// @version      0.1.0
// @description  Modifiable answer checker in reviews and lessons
// @author       polv
// @match        https://www.wanikani.com/*
// @match        https://preview.wanikani.com/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=wanikani.com
// @license      MIT
// @source       https://github.com/patarapolw/wanikani-userscript/blob/master/userscripts/answer-checker.user.js
// @grant        none
// ==/UserScript==

// @ts-check
/// <reference path="./types/answer-checker.d.ts" />
(function () {
  class ModAnswerChecker {
    /**
     * @type {TryEvaluationFunction[]}
     */
    mods = [];
    /**
     * @type {{
     *   oldEvaluate?: EvaluationFunction
     *   evaluate: EvaluationFunction
     * } | null}
     */
    answerChecker = null;

    /**
     *
     * @param {TryEvaluationFunction} fn
     */
    register(fn) {
      this.mods.push(fn);
    }

    constructor() {
      // Automatically init on new instance
      window.addEventListener('turbo:load', (e) => {
        // @ts-ignore
        const url = e.detail.url;
        if (!url) return;

        /**
         * e.g.
         * https://www.wanikani.com/subjects/lesson/quiz?queue=${subjectIds.join('-')}
         * https://www.wanikani.com/subjects/review
         * https://www.wanikani.com/subjects/extra_study?queue_type=${queueType}
         */
        if (/(session|quiz|review|extra_study)/.test(url)) {
          // @ts-ignore
          const Stimulus = window.Stimulus;
          if (!Stimulus) return;

          const startDate = +new Date();
          const intervalId = setInterval(() => {
            this.answerChecker =
              Stimulus.controllers.find((x) => {
                return x.answerChecker;
              })?.answerChecker || null;

            if (this.answerChecker) {
              clearInterval(intervalId);

              if (this.answerChecker.oldEvaluate) return;
              const answerChecker = this.answerChecker;

              console.log('Found new answerChecker');

              const oldEvaluate = answerChecker.evaluate.bind(answerChecker);
              answerChecker.oldEvaluate = oldEvaluate;

              /** @type {(fns: TryEvaluationFunction[]) => EvaluationFunction} */
              const evaluateWith = (fns) => {
                return (e) => {
                  for (const fn of fns) {
                    const r = fn(
                      e,
                      evaluateWith(fns.filter((it) => it !== fn)),
                    );
                    if (r) return r;
                  }
                  return oldEvaluate(e);
                };
              };

              answerChecker.evaluate = evaluateWith(this.mods);
            }

            if (startDate + 5000 < +new Date()) {
              clearInterval(intervalId);
            }
          }, 500);
        }
      });
    }
  }

  window.modAnswerChecker = window.modAnswerChecker || new ModAnswerChecker();
})();