Function Key

docs/app/js/sanddance-app.js:117867–117869

* Generates a key function. * @constructor * @param {object} params - The parameters for this operator. * @param {Array } params.fields - The field name(s) for the key function. * @param {boolean} params.flat - A boolean flag indicating if the field names * should be treated as flat pro

(params)

 *  should be treated as flat property names, side-stepping nested field
 *  lookups normally indicated by dot or bracket notation.
 */ function Key(params) {
    (0, _vegaDataflow.Operator).call(this, null, update$2, params);
}
(0, _vegaUtil.inherits)(Key, (0, _vegaDataflow.Operator));
function update$2(_) {
    return this.value && !_.modified() ? this.value : (0, _vegaUtil.key)(_.fields, _.flat);