vditor/src/ts/toolbar/Undo.ts

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import {Constants} from "../constants";
import {getEventName} from "../util/compatibility";
import {MenuItem} from "./MenuItem";
import {disableToolbar} from "./setToolbar";

export class Undo extends MenuItem {
    constructor(vditor: IVditor, menuItem: IMenuItem) {
        super(vditor, menuItem);
        disableToolbar({undo: this.element}, ["undo"]);
        this.element.children[0].addEventListener(getEventName(), (event) => {
            event.preventDefault();
            if (this.element.firstElementChild.classList.contains(Constants.CLASS_MENU_DISABLED)) {
                return;
            }
            vditor.undo.undo(vditor);
        });
    }
}