extremal-doc-subscribe.js

    /**
     * Bind injections from the specified SFC layer to the supplied document.
     * @param {String} layerName - The name of the layer for which injections are to be bound
     * @param {Document} dokkument - The document object into which any injection directives will be injected
     * @return {Signal<Boolean>} - A signal which resolves to `true` when injections are resolved
     */
    fluid.subscribeDocToInjections = function (layerName, dokkument) {
        const rec = fluid.readSFC(layerName);
        // TODO: One day clear these out
        let docEffect = rec.docInjectEffects.get(dokkument);
        if (!docEffect) {
            /** @type {Object<String, InjectRecord>} **/
            let oldInjRecs = {};
            const injDone = signal(fluid.unavailable("Injection in progress"));
            injDone.layerName = layerName;
            injDone.dokkument = dokkument;
            const newDocEffect = fluid.effect(async function docInjectEffect(injRecs) {
                fluid.startBufferDefs();
                try {
                    /** @type {DocInjectionRecord[]} */
                    const docInjRecs = Object.values(injRecs).map(injRec =>
                        fluid.decodeInjectSFCElement(dokkument, injRec, rec.url, oldInjRecs,
                            injRec.variety === "script" ? fluid.scriptInjectionStyles : fluid.cssInjectionStyles)
                    ).filter(injRec => injRec);
                    const injsDone = docInjRecs.map(docInjRec => fluid.doInjectSFCElement(docInjRec));
                    const injsDoneSignal = fluid.signalsToAvailable(injsDone);
                    const res = fluid.signalToPromise(injsDoneSignal);
                    await res;
                    console.log(`Await for ${layerName} is done`);
                } finally {
                    console.log(`Finally for ${layerName} is starting`);
                    // Don't actually register layers until all the rest of the code has executed
                    fluid.endBufferDefs();
                    injDone.value = true;
                }

                Object.keys(oldInjRecs).forEach(nodeId => {
                    const newRec = injRecs[nodeId];
                    if (!newRec) {
                        fluid.clearInjRec(nodeId);
                    }
                });
                oldInjRecs = injRecs;
            }, [rec.injRecsSignal]);
            newDocEffect.injDone = injDone;
            rec.docInjectEffects.set(dokkument, newDocEffect);
            fluid.noteLayerInjectionInProgress(injDone);
            docEffect = newDocEffect;
        }
        return docEffect.injDone;
    };