core-graphics/lib/event-sourcing/event-sourcing.js

A core library for creating shape-based graphic editors

"use strict";

Object.defineProperty(exports, "__esModule", {
    value: true
});
exports.getUndoEvent = getUndoEvent;
exports.getRedoEvent = getRedoEvent;
function getUndoEvent(history, author) {
    if (history.length === 0) {
        return null;
    }
    for (var i = history.length - 1; i >= 0; i--) {
        var ev = history[i];
        if (ev.author === author && ev.applied === true) {
            return ev;
        }
    }
    return null;
}
function getRedoEvent(history, author) {
    if (history.length === 0) {
        return null;
    }
    var lastUnappliedAuthorEvent = null;
    for (var i = history.length - 1; i >= 0; i--) {
        var ev = history[i];
        if (ev.author === author && ev.applied === false) {
            lastUnappliedAuthorEvent = ev;
            continue;
        }
        if (ev.author === author && ev.applied === true) {
            return lastUnappliedAuthorEvent;
        }
    }
    return lastUnappliedAuthorEvent;
}