尝试在node.js和cylon.js上平滑代码，但语法失败

Question

我是JavaScript的新手，一直在尝试给Leap Motion的输出数据添加一个平滑过滤器。我使用Cylon.js获得数据，它基本上输出3个值(x，y和z)。然而，我不能让平滑代码工作，我想这是因为我习惯了C/C++语法，可能做错了什么。

代码是这样的：

"use strict";

var Cylon = require("cylon");

var numReadings = 20;

var readings[numReadings];
var readIndex = 0;
var total = 0;
var average = 0;

for (var thisReading = 0; thisReading < numReadings; thisReading++) {
    readings[thisReading] = 0;
}

Cylon.robot({
    connections: {
        leapmotion: {
            adaptor: "leapmotion"
        }
    },

    devices: {
        leapmotion: {
            driver: "leapmotion"
        }
    },

    work: function(my) {
        my.leapmotion.on("hand", function(hand) {
            console.log(hand.palmPosition.join(","));

            // subtract the last reading:
            total = total - readings[readIndex];
            // read from the sensor:
            readings[readIndex] = hand.palmPosition;
            // add the reading to the total:
            total = total + readings[readIndex];
            // advance to the next position in the array:
            readIndex = readIndex + 1;

            // if we're at the end of the array...
            if (readIndex >= numReadings) {
                // ...wrap around to the beginning:
                readIndex = 0;
            }

            // calculate the average:
            average = total / numReadings;
            console.log(average);
        });
    }
}).start();

因此，我试图过滤的数据是"hand.palmPosition“。但它在控制台上给出了以下错误：

​

​

如有任何帮助，我们不胜感激！

谢谢

Answer 1

无效的JS：

var readings[numReadings];

看起来你想让readings成为一个数组。您不需要初始化JS数组的大小。要创建数组，请执行以下操作：

var readings = [];

要用零填充它：

for (var thisReading = 0; thisReading < numReadings; thisReading++) {
  readings.push[0];
}