swaf/src/components/FormHelperComponent.ts

import {Router} from "express";

import ApplicationComponent from "../ApplicationComponent.js";
import FrontendToolsComponent from "./FrontendToolsComponent.js";

export default class FormHelperComponent extends ApplicationComponent {

    public async init(): Promise<void> {
        const globals = this.getApp().asOptional(FrontendToolsComponent)?.getGlobals();
        if (globals) {
            globals.set('validation', () => ({}));
            globals.set('previousFormData', () => ({}));
        }
    }

    public async initRoutes(router: Router): Promise<void> {
        router.use((req, res, next) => {
            let _validation: unknown | null;
            res.locals.validation = () => {
                if (!_validation) {
                    const v = req.flash('validation');
                    _validation = v.length > 0 ? v[0] : null;
                }

                return _validation;
            };

            let _previousFormData: unknown | null = null;
            res.locals.previousFormData = () => {
                if (!_previousFormData) {
                    const v = req.flash('previousFormData');
                    _previousFormData = v.length > 0 ? v[0] : null;
                }

                return _previousFormData;
            };
            next();
        });

        router.use((req, res, next) => {
            if (['GET', 'POST'].find(m => m === req.method)) {
                if (typeof req.body === 'object' && Object.keys(req.body).length > 0) {
                    req.flash('previousFormData', req.body);
                }
            }
            next();
        });
    }
}