@themost/data/OnExecuteNestedQueryable.js

MOST Web Framework Codename Blueshift - Data module

// MOST Web Framework 2.0 Codename Blueshift BSD-3-Clause license Copyright (c) 2017-2021, THEMOST LP All rights reserved

// eslint-disable-next-line no-unused-vars
const { DataEventArgs } = require('./types');
require('@themost/promise-sequence');

class OnExecuteNestedQueryable {
    beforeExecute(event, callback) {
        OnExecuteNestedQueryable.prototype.beforeExecuteAsync(event).then(function() {
            return callback();
        }).catch(function(err) {
            return callback(err);
        });
    }
    /**
     * @param {DataEventArgs} event 
     */
    beforeExecuteAsync(event) {
        const query = event.emitter && event.emitter.query;
        const context = event.model.context;
        if (query == null) {
            return Promise.resolve();
        }
        if (Object.prototype.hasOwnProperty.call(query, '$expand')) {
            /**
             * @type {{ $entity:{ model:string }} | Array<{ $entity:{ model:string }}>}
             */
            const expand = query.$expand;
            // exit if expand is null or undefined
            if (expand == null) {
                return Promise.resolve();
            }
            if (Array.isArray(expand)) {
                const sources = expand.map(function(item) {
                    return function() {
                        if (item.$entity && item.$entity.model) {
                            // get nested model
                            const model = context.model(item.$entity.model);
                            // if model exists and it's different from the current model
                            if (model != null && event.model.name !== model.name) {
                                // try to upgrade
                                return model.migrateAsync();
                            }
                            if (model == null) {
                                // try to find if the given model is a pre-defined many-to-many association
                                const attribute = event.model.attributes.filter((attr) => attr.many).find((attr) => {
                                    const mapping = event.model.inferMapping(attr.name);
                                    return mapping && mapping.associationAdapter === item.$entity.model;
                                });
                                if (attribute) {
                                    /**
                                     * use DataObjectJunction class as a helper for creating model
                                     * (get an instance of DataObjectJunction class using DataObject.property() method)
                                     * @type {import('./data-object-junction').DataObjectJunction}
                                     */
                                    const junction = event.model.convert({}).property(attribute.name);
                                    return junction.getBaseModel().migrateAsync();
                                }
                            }
                        }
                        return Promise.resolve();
                    }
                });
                return Promise.sequence(sources);
            } else if (expand && expand.$entity && expand.$entity.model) {
                // get nested model
                const model = context.model(expand.$entity.model);
                if (model != null && event.model.name !== model.name) {
                    // try to upgrade
                    return model.migrateAsync();
                }
            }
        }
        return Promise.resolve();
    }
}

module.exports = {
    OnExecuteNestedQueryable
}