node-red-nodes/function/smooth/17-smooth.js

/**
 * Copyright 2014 IBM Corp.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 **/

var RED = require(process.env.NODE_RED_HOME + "/red/red");

function SmoothNode(n) {
    RED.nodes.createNode(this, n);
    this.action = n.action;
    this.round = n.round || false;
    this.count = Number(n.count);
    var node = this;
    var a = [];
    var tot = 0;
    var pop = 0;
    var old = null;

    this.on('input', function (msg) {
        var n = Number(msg.payload);
        if (!isNaN(n)) {
            if ((node.action === "low") || (node.action === "high")) {
                if (old == null) { old = n; }
                old = old + (n - old) / node.count;
                if (node.action === "low") { msg.payload = old; }
                else { msg.payload = n - old; }
            }
            else {
                a.push(n);
                if (a.length > node.count) { pop = a.shift(); }
                if (node.action === "max") {
                    msg.payload = Math.max.apply(Math, a);
                }
                if (node.action === "min") {
                    msg.payload = Math.min.apply(Math, a);
                }
                if (node.action === "mean") {
                    tot = tot + n - pop;
                    msg.payload = tot / a.length;
                }
            }
            if (node.round) { msg.payload = Math.round(msg.payload); }
            node.send(msg);
        }
        else { node.log("Not a number: "+msg.payload); }
    });
}
RED.nodes.registerType("smooth", SmoothNode);