pondjs/src/pond/lib/processors/selector.js

A timeseries library build on top of immutable.js

/**
 *  Copyright (c) 2016-2017, The Regents of the University of California,
 *  through Lawrence Berkeley National Laboratory (subject to receipt
 *  of any required approvals from the U.S. Dept. of Energy).
 *  All rights reserved.
 *
 *  This source code is licensed under the BSD-style license found in the
 *  LICENSE file in the root directory of this source tree.
 */

import Processor from "./processor";

import Event from "../event";
import { isPipeline } from "../pipeline";

/**
 * A processor which takes a fieldSpec as its only argument
 * and returns a new event with only those selected columns
 */
export default class Selector extends Processor {
    constructor(arg1, options) {
        super(arg1, options);

        if (arg1 instanceof Selector) {
            const other = arg1;
            this._fieldSpec = other._fieldSpec;
        } else if (isPipeline(arg1)) {
            this._fieldSpec = options.fieldSpec;
        } else {
            throw new Error("Unknown arg to filter constructor", arg1);
        }
    }

    clone() {
        return new Selector(this);
    }

    addEvent(event) {
        if (this.hasObservers()) {
            this.emit(Event.selector(event, this._fieldSpec));
        }
    }
}