gatsby-source-sanity/lib/util/createTemporaryMockNodes.js

Gatsby source plugin for building websites using Sanity.io as a backend.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const removeGatsbyInternalProps_1 = require("./removeGatsbyInternalProps");
const cache_1 = require("./cache");
const remoteGraphQLSchema_1 = require("./remoteGraphQLSchema");
const debug_1 = require("../debug");
/**
 * Gatsby doesn't generate collection queries for declared third-party schemas,
 * and declaring a schema also causes all sorts of weird and hard to debug problems.
 *
 * This function reads a generated type map of a remote GraphQL schema and generates
 * example values for each schema type, then creates Gatsby nodes for each type,
 * which results in Gatsby generating queries and schema types that have all the
 * possible fields included. Once the schema is created, we remove the mock nodes
 * so they are not returned in queries. This is done through a bit of a hack,
 * which utilizes the exposed `emitter` on the Gatsby context and listening for
 * the `SET_SCHEMA` action to occur. These are internals and might change in the
 * future, but we rely on them for now because the alternative is to require data
 * to be present and have representative values in all fields before one can start
 * writing queries.
 *
 * There is a community effort (with Gatsby HQ support upcoming) to introduce a
 * proper API for declaring schema types, which will make this hack unnecessary.
 * Until it lands, this is the best we can do.
 */
async function createTemporaryMockNodes(context, pluginConfig, stateCache) {
    const { emitter, actions, reporter } = context;
    const { createNode, deleteNode } = actions;
    // Sanity-check (heh) some undocumented, half-internal APIs
    const canMock = emitter && typeof emitter.on === 'function' && typeof emitter.off === 'function';
    if (!canMock) {
        reporter.warn('[sanity] `emitter` API not received, Gatsby internals might have changed');
        reporter.warn('[sanity] Please create issue: https://github.com/sanity-io/gatsby-source-sanity');
        return;
    }
    const typeMapKey = cache_1.getCacheKey(pluginConfig, cache_1.CACHE_KEYS.TYPE_MAP);
    const typeMap = (stateCache[typeMapKey] || remoteGraphQLSchema_1.defaultTypeMap);
    const exampleValues = typeMap.exampleValues;
    const exampleTypes = exampleValues && Object.keys(exampleValues);
    if (!exampleTypes || exampleTypes.length === 0) {
        if (Object.keys(typeMap.objects).length > 0) {
            reporter.warn('[sanity] No example values generated, fields might be missing!');
        }
        return;
    }
    const onSchemaUpdate = () => {
        debug_1.default('Schema updated, removing mock nodes');
        exampleTypes.forEach(typeName => {
            deleteNode({ node: exampleValues[typeName] });
        });
        emitter.off('SET_SCHEMA', onSchemaUpdate);
    };
    debug_1.default('Creating mock nodes with example value');
    exampleTypes.forEach(typeName => {
        createNode(removeGatsbyInternalProps_1.removeGatsbyInternalProps(exampleValues[typeName]));
    });
    emitter.on('SET_SCHEMA', onSchemaUpdate);
}
exports.createTemporaryMockNodes = createTemporaryMockNodes;
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