apps.apple.com/node_modules/@jet/environment/metrics/parse-and-build-model.js

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.parseAndBuildModel = exports.requestAndBuildModel = void 0;
const dependencies_1 = require("../dependencies");
const optional_1 = require("../types/optional");
const fetch_timing_metrics_builder_1 = require("./fetch-timing-metrics-builder");
/**
 * Returns an object graph guaranteed to have a `FetchTimingMetricsBuilder` object.
 *
 * If a `FetchTimingMetricsBuilder` already exists, the same object graph is returned.
 *
 * If it doesn't exist, a new object graph is returned, which has a new `FetchTimingMetricsBuilder` added to it.
 */
function ensureFetchTimingMetricsBuilderExists(objectGraph, errorIfNotFound) {
    const optionalBuilder = objectGraph.optional(fetch_timing_metrics_builder_1.fetchTimingMetricsBuilderType);
    if ((0, optional_1.isSome)(optionalBuilder)) {
        return objectGraph;
    }
    else {
        if (errorIfNotFound) {
            throw new Error("Could not find FetchTimingMetricsBuilder in the object graph");
        }
        return objectGraph.adding(fetch_timing_metrics_builder_1.fetchTimingMetricsBuilderType, new fetch_timing_metrics_builder_1.FetchTimingMetricsBuilder());
    }
}
/**
 * Orchestrates the flow to make a network request and then build the view model,
 * capturing timing points around the model building step, and then
 * adding performance metrics data to the final result.
 *
 * **Important**
 *
 * When using this method, it is the responsibility of the `requester` to instrument the network times and parsing times
 * using a `FetchTimingMetricsBuilder` which is in the object graph.
 *
 * A simplified implementation of a requester function might look like this:
```
    import * as types from "@jet/environment/types/globals/types"
    import { fetchTimingMetricsBuilderType } from "@jet/environment/metrics";

    export async function requestFromAPI(request: FetchRequest, objectGraph: ObjectGraph): Promise<MyParsedModel> {
        const net = inject(types.net, objectGraph);
        const fetchResponse = await net.fetch(request);
        const fetchTimingMetricsBuilder = inject(fetchTimingMetricsBuilderType, objectGraph);
        return fetchTimingMetricsBuilder.measureParsing(fetchResponse, (response) => {
            const parsedBody = JSON.parse(response.body);
            return new MyParsedModel(parsedBody);
        });
    }
```
 * This approach supports a common pattern in our adopters in which the code that coordinates the fetch of the network request
 * is tightly coupled to the code which parses the response.
 *
 * For an alternative approach which includes orchestrating the parsing step, use `parseAndBuildModel()`.
 *
 * @param request - The request object to pass to the `requester` function.
 * @param objectGraph - Object graph that can be used to pass data to the `requester` and `modelBuilder` steps.
 * The object graph must contain a `FetchTimingMetricsBuilder` that the `requester` will use to collect network times and parsing times.
 * @param requester - A function which can make a network request, and return a `ResponseType` which can be used by the `modelBuilder`.
 * @param modelBuilder - A step that takes the output of the `requester` step, and builds the view model.
 * This parameter supports both synchronous and asynchronous functions.
 * @returns The view model.
 */
async function requestAndBuildModel(request, objectGraph, requester, modelBuilder) {
    const modifiedObjectGraph = ensureFetchTimingMetricsBuilderExists(objectGraph, true);
    const response = await requester(request, modifiedObjectGraph);
    return await constructAndDecorateModel(response, modifiedObjectGraph, modelBuilder);
}
exports.requestAndBuildModel = requestAndBuildModel;
/**
 * Orchestrates the flow to parse a `FetchResponse` and then build the view model,
 * adding performance metrics data to the final result.
 *
 * Timing points are captured around the parsing and model building steps,
 * and this is added to the metrics which were returned from the `FetchResponse`.
 *
 * When using this method, it is the responsibility of the caller
 * to perform the network fetch in order to have a `FetchResponse` object.
 * The parsing logic which transforms the `FetchResponse` object into an intermediate model object
 * will need to be decoupled so that it can be implemented in the `parser` function.
 *
 * @param response - The response from a `Network.fetch()` call.
 * @param objectGraph - Object graph that can be used to pass data to the `parser` and `renderer` steps.
 * @param parser - A step that parses a `FetchResponse` to an intermediate model object.
 * @param modelBuilder - A step that takes the output of the `parser` step, and builds the view model.
 * This parameter supports both synchronous and asynchronous functions.
 * @returns The view model.
 */
async function parseAndBuildModel(response, objectGraph, parser, modelBuilder) {
    const modifiedObjectGraph = ensureFetchTimingMetricsBuilderExists(objectGraph, false);
    const fetchTimingMetricsBuilder = (0, dependencies_1.inject)(fetch_timing_metrics_builder_1.fetchTimingMetricsBuilderType, modifiedObjectGraph);
    // Add metrics from FetchResponse, and run the parser, capturing timing points.
    const parsedObject = fetchTimingMetricsBuilder.measureParsing(response, () => {
        return parser(response, modifiedObjectGraph);
    });
    if ((0, optional_1.isNothing)(parsedObject)) {
        throw new Error("parser function returned null or undefined");
    }
    return await constructAndDecorateModel(parsedObject, modifiedObjectGraph, modelBuilder);
}
exports.parseAndBuildModel = parseAndBuildModel;
async function constructAndDecorateModel(parsedObject, objectGraph, modelBuilder) {
    const fetchTimingMetricsBuilder = (0, dependencies_1.inject)(fetch_timing_metrics_builder_1.fetchTimingMetricsBuilderType, objectGraph);
    // Run the model builder, capturing timing points.
    const model = await fetchTimingMetricsBuilder.measureModelConstructionAsync(async () => {
        const maybePromise = modelBuilder(parsedObject, objectGraph); // The actual model, or a Promise of the model.
        return await Promise.resolve(maybePromise); // If it was promise, it will await until the promise is resolved.
    });
    if ((0, optional_1.isNothing)(model)) {
        throw new Error("model builder function returned null or undefined");
    }
    // Decorate the final output with the metrics data.
    fetchTimingMetricsBuilder.decorate(model);
    return model;
}
//# sourceMappingURL=parse-and-build-model.js.map