TypeError: Class constructor Wia cannot be invoked without 'new'

Question

这是我在 json 文件中的代码，每当我尝试运行它时，我都会收到此错误： TypeError: Class 没有 'new' 就无法调用构造函数 Wia 在对象。 (/home/pi/wia-pi-camera/run-camera.js:3:25)

'use strict';

var wia = require('wia')('your-device-secret-key');
var fs = require('fs');
var RaspiCam = require("raspicam");

// Setup the camera
var camera = new RaspiCam({
  mode: 'photo',
  output: __dirname + '/photo.jpg',
  encoding: 'jpg'
});

// Listen for the "start" event triggered when the start method has been successfully initiated
camera.on("start", function(){
  console.log("Starting to take photo.");
});

// Listen for the "read" event triggered when each new photo/video is saved
camera.on("read", function(err, timestamp, filename){
  console.log("New photo created.", timestamp, filename);

  // Publish the photo to Wia
  wia.events.publish({
    name: 'photo',
    file:  fs.createReadStream(__dirname + '/' + filename)
  });
});

// Take a photo
camera.start();

第二行似乎是错误发生的地方：var wia = require('wia')('my_device_secret_key');

有谁知道如何解决这个问题？

Answer 1

试试这样：

const Wia = require('wia');
var wia = new Wia('your-device-secret-key');

require('wia')returns一个class，你需要用new调用它来创建一个实例。

TypeError: Class constructor Wia cannot be invoked without 'new'

TypeError: Class constructor Wia cannot be invoked without 'new'

javascript

terminal

json

node.js

raspberry-pi