| 1 | import {Operator} from 'vega-dataflow';
|
| 2 | import {array, field, inherits, isArray} from 'vega-util';
|
| 3 |
|
| 4 | /**
|
| 5 | * Generates one or more field accessor functions.
|
| 6 | * If the 'name' parameter is an array, an array of field accessors
|
| 7 | * will be created and the 'as' parameter will be ignored.
|
| 8 | * @constructor
|
| 9 | * @param {object} params - The parameters for this operator.
|
| 10 | * @param {string} params.name - The field name(s) to access.
|
| 11 | * @param {string} params.as - The accessor function name.
|
| 12 | */
|
| 13 | export default function Field(params) {
|
| 14 | Operator.call(this, null, update, params);
|
| 15 | }
|
| 16 |
|
| 17 | inherits(Field, Operator);
|
| 18 |
|
| 19 | function update(_) {
|
| 20 | return (this.value && !_.modified()) ? this.value
|
| 21 | : isArray(_.name) ? array(_.name).map(f => field(f))
|
| 22 | : field(_.name, _.as);
|
| 23 | }
|