Function TupleIndex

docs/app/js/sanddance-app.js:118661–118663

* An index that maps from unique, string-coerced, field values to tuples. * Assumes that the field serves as a unique key with no duplicate values. * @constructor * @param {object} params - The parameters for this operator. * @param {function(object): *} params.field - The field accessor to inde

(params)

 * @param {object} params - The parameters for this operator.
 * @param {function(object): *} params.field - The field accessor to index.
 */ function TupleIndex(params) {
    (0, _vegaDataflow.Transform).call(this, (0, _vegaUtil.fastmap)(), params);
}
(0, _vegaUtil.inherits)(TupleIndex, (0, _vegaDataflow.Transform), {
    transform (_, pulse) {
        const df = pulse.dataflow, field = _.field, index = this.value, set2 = (t)=>index.set(field(t), t);