@ima/core/dist/esm/client/page/handler/PageMetaHandler.js

IMA.js framework for isomorphic javascript application

import { PageHandler } from './PageHandler';
import { MetaManager } from '../../meta/MetaManager';
import { Window } from '../../window/Window';
export const IMA_META_DATA_ATTR = 'data-ima-meta';
export class PageMetaHandler extends PageHandler {
    #window;
    #metaManager;
    #managed = false;
    static get $dependencies() {
        return [
            Window,
            MetaManager
        ];
    }
    constructor(window, metaManager){
        super();
        this.#window = window;
        this.#metaManager = metaManager;
    }
    /**
   * @inheritDoc
   */ handlePreManagedState() {
        this.#metaManager.clearMetaAttributes();
    }
    /**
   * @inheritDoc
   */ handlePostManagedState() {
        // Skip first manage state after SSR, so we don't
        if (!this.#window.getWindow()?.$IMA?.SPA && !this.#managed && this.#selectMetaTags().length) {
            this.#managed = true;
            return;
        }
        this.#updateMetaAttributes();
    }
    /**
   * Update specified meta or link tags in DOM.
   *
   * @param metaManager meta attributes storage providing the
   *        new values for page meta elements and title.
   */ #updateMetaAttributes() {
        this.#window.setTitle(this.#metaManager.getTitle());
        // Remove IMA managed meta tags
        this.#selectMetaTags().forEach((el)=>el?.remove());
        // Set title
        this.#window.setTitle(this.#metaManager.getTitle());
        // Update meta tags
        this.#updateMetaTag(this.#metaManager.getLinksIterator(), 'link', 'rel');
        this.#updateMetaTag(this.#metaManager.getMetaNamesIterator(), 'meta', 'name');
        this.#updateMetaTag(this.#metaManager.getMetaPropertiesIterator(), 'meta', 'property');
    }
    /**
   * Helper to update specific meta tags in page document.
   *
   * @param iterator Collection of meta records to update.
   * @param tagName Tag name for the given collection.
   * @param valueName Name of the main value for given meta collection.
   */ #updateMetaTag(iterator, tagName, keyName) {
        const document = this.#window.getDocument();
        for (const [key, value] of iterator){
            const attributes = {
                [keyName]: key,
                ...value
            };
            const metaTag = document.createElement(tagName);
            metaTag.setAttribute(IMA_META_DATA_ATTR, '');
            for (const [attrName, attrValue] of Object.entries(attributes)){
                const sanitizedAttrValue = this.#sanitizeValue(attrValue);
                // Skip empty values
                if (sanitizedAttrValue === null) {
                    continue;
                }
                metaTag.setAttribute(attrName, sanitizedAttrValue);
            }
            document?.head?.appendChild(metaTag);
        }
    }
    #sanitizeValue(value) {
        return value === undefined || value === null ? null : value.toString();
    }
    #selectMetaTags() {
        return this.#window.querySelectorAll(`[${IMA_META_DATA_ATTR}]`);
    }
}

//# sourceMappingURL=PageMetaHandler.js.map