@benev/slate/x/watch/framework/historian.js

frontend web stuff

import { History } from "./utils/history.js";
import { watch } from "../../nexus/state.js";
import { history_actualize } from "./utils/actualize.js";
import { find_in_blueprint } from "./utils/find_in_blueprint.js";
import { record_snapshot, trim_to_history_limit } from "./utils/history_tools.js";
export class Historian {
    tree;
    blueprint;
    history_limit;
    #annals;
    actions;
    history;
    constructor(tree, blueprint, history_limit) {
        this.tree = tree;
        this.blueprint = blueprint;
        this.history_limit = history_limit;
        this.#annals = watch.stateTree({
            snapshots: [],
            past: [],
            future: [],
        });
        this.actions = history_actualize({
            blueprint,
            tree,
            save_snapshot: this.save_snapshot.bind(this),
            proceed: this.proceed.bind(this),
        });
        this.history = new History(this.#annals, this);
    }
    save_snapshot() {
        this.#annals.transmute(annals => {
            record_snapshot(annals, this.tree.state, this.history_limit);
            return annals;
        });
    }
    proceed(action) {
        this.#annals.transmute(annals => {
            annals.past.push(action);
            trim_to_history_limit(annals.past, this.history_limit);
            annals.future = [];
            return annals;
        });
    }
    undo() {
        this.#annals.transmute(annals => {
            const { past, future, snapshots } = annals;
            if (past.length > 0 && snapshots.length > 0) {
                const action = past.pop();
                const previous_state = snapshots.pop();
                future.push(action);
                this.tree.transmute(() => previous_state);
            }
            return annals;
        });
    }
    redo() {
        this.#annals.transmute(annals => {
            const action = annals.future.pop();
            if (action) {
                const fn = find_in_blueprint(this.blueprint, action.purpose);
                if (!fn)
                    throw new Error(`unknown action "${action.purpose}"`);
                this.tree.transmute(state => {
                    record_snapshot(annals, state, this.history_limit);
                    const setState = (newState) => { state = newState; };
                    fn(state, setState)(...action.params);
                    return state;
                });
                annals.past.push(action);
            }
            return annals;
        });
    }
}
//# sourceMappingURL=historian.js.map