ra-core/src/inference/getValuesFromRecords.ts

Core components of react-admin, a frontend Framework for building admin applications on top of REST services, using ES6, React

/**
 * Gets a list of values indexed by field based on a list of records
 *
 * @example
 * const records = [
 *     {
 *         id: 1,
 *         title: "Lorem Ipsum",
 *         views: 254,
 *         user_id: 123,
 *     },
 *     {
 *         id: 2,
 *         title: "Sic Dolor amet",
 *         views: 65,
 *         user_id: 456,
 *     },
 * ];
 * getValuesFromRecords(records);
 * // {
 * //    id: [1, 2],
 * //    title: ['Lorem Ipsum', 'Sic Dolor amet'],
 * //    views: [254, 65],
 * //    user_id: [123, 456],
 * // }
 */
export default (records: any[]) =>
    records.reduce((values, record) => {
        Object.keys(record).forEach(fieldName => {
            if (!values[fieldName]) {
                values[fieldName] = [];
            }
            if (record[fieldName] != null) {
                const value = Array.isArray(record[fieldName])
                    ? [record[fieldName]]
                    : record[fieldName];
                values[fieldName] = values[fieldName].concat(value);
            }
        });
        return values;
    }, {});