@dwp/govuk-casa/dist/middleware/data.js

A framework for building GOVUK Collect-And-Submit-Applications

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.default = dataMiddleware;
const JourneyContext_js_1 = __importDefault(require("../lib/JourneyContext.js"));
const utils_js_1 = require("../lib/utils.js");
const waypoint_url_js_1 = __importDefault(require("../lib/waypoint-url.js"));
/**
 * @typedef {import("express").RequestHandler} RequestHandler
 * @access private
 */
/**
 * @typedef {import("../casa.js").Plan} Plan
 * @access private
 */
/**
 * @typedef {import("../casa.js").ContextEventHandler} ContextEventHandler
 * @access private
 */
/**
 * @typedef {import("../casa.js").ContextIdGenerator} ContextIdGenerator
 * @access private
 */
const editOrigin = (req) => {
    if (Object.hasOwn(req.query, "editorigin")) {
        return (0, waypoint_url_js_1.default)({ waypoint: req.query.editorigin });
    }
    if (req.body && Object.hasOwn(req.body, "editorigin")) {
        return (0, waypoint_url_js_1.default)({ waypoint: req.body.editorigin });
    }
    return "";
};
/**
 * Data middleware.
 *
 * Decorates the request with some contextual data about the user's journey
 * through the application. This is used by downstream middleware and
 * templates.
 *
 * @param {object} opts Options
 * @param {Plan} opts.plan CASA Plan
 * @param {ContextEventHandler[]} opts.events Event handlers
 * @param {ContextIdGenerator} opts.contextIdGenerator Content ID generator
 * @param {boolean} ops.govukRebrand Govuk rebrand feature flag
 * @param opts.govukRebrand
 * @returns {RequestHandler[]} Middleware functions
 */
function dataMiddleware({ plan, events, contextIdGenerator, govukRebrand, }) {
    return [
        (req, res, next) => {
            /* ------------------------------------------------ Request decorations */
            // CASA
            req.casa = {
                ...req?.casa,
                // The plan
                plan,
                // Current journey context, loaded from session, specified by
                // `contextid` request parameter
                journeyContext: JourneyContext_js_1.default.extractContextFromRequest(req).addEventListeners(events),
                // Edit mode
                editMode: (Object.hasOwn(req.query, "edit") &&
                    Object.hasOwn(req.query, "editorigin")) ||
                    (Object.hasOwn(req.body, "edit") &&
                        Object.hasOwn(req.body, "editorigin")),
                editOrigin: editOrigin(req),
            };
            // Grab chosen language from session
            req.casa.journeyContext.nav.language = req.session.language;
            // Context ID generator
            Object.defineProperty(req, JourneyContext_js_1.default.ID_GENERATOR_REQ_KEY, {
                value: contextIdGenerator,
                enumerable: false,
                writable: false,
            });
            /* ------------------------------------------------- Template variables */
            // Capture mount URL that will be used in generating all browser URLs
            const mountUrl = (0, utils_js_1.validateUrlPath)(`${req.baseUrl}/`.replace(/\/+/g, "/"));
            // If this CASA app is mounted on a parameterised route, then all of its
            // static assets (served by `staticRouter`) will, by default, be served
            // from that dynamic path, for example:
            //   markup:       <link href="{{ mountUrl }}css/static.css" />
            //   resolved URL: /mount/<some-id-here>/css/static.css
            //   baseUrl:      /mount/<some-id>
            //
            // From a performance point of view, this is very inefficient as we can't
            // take advantage of any intermediate caches. So we instead provide am
            // alternative URL path in the `staticMountUrl` property that excludes the
            // parameterised element, eg:
            //   markup:       <link href="{{ staticMountUrl }}css/static.css" />
            //   resolved URL: /mount/css/static.css
            //   baseUrl:      /mount
            //
            // As the staticRouter is mounted on both the CASA app, and its internal
            // Router, the `baseUrl` is different in each case, so we cannot rely
            // on it to be consistent. Hence the need for this property, which will
            // always be the non-parameterised version of the baseUrl.
            const staticMountUrl = (0, utils_js_1.validateUrlPath)(`${req.unparameterisedBaseUrl}/`.replace(/\/+/g, "/"));
            // CASA and userland templates
            res.locals.casa = {
                mountUrl,
                staticMountUrl,
                editMode: req.casa.editMode,
                editOrigin: req.casa.editOrigin,
            };
            res.locals.locale = req.language;
            // Used by govuk-frontend template
            //   htmlLang = req.language is provided by i18n-http-middleware
            //   assetPath = used for linking to static assets in the govuk-frontend module
            res.locals.htmlLang = req.language;
            const rebrandAssetPath = govukRebrand ? "/rebrand" : "";
            res.locals.assetPath = `${staticMountUrl}govuk/assets${rebrandAssetPath}`;
            // Function for building URLs. This will be curried with the `mountUrl`,
            // `journeyContext`, `edit` and `editOrigin` for convenience. This means
            // the template author does not have to be concerned about the current
            // "state" when generating URLs, but still has the ability to override
            // these curried defaults if needs be.
            res.locals.waypointUrl = (args) => (0, waypoint_url_js_1.default)({
                mountUrl,
                journeyContext: req.casa.journeyContext,
                edit: req.casa.editMode,
                editOrigin: req.casa.editOrigin,
                ...args,
            });
            next();
        },
    ];
}
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