在NodeJS处传递的图像文件参数

Question

I have a method from where I pass a text and image file as a parameter to another function. The text is passed but the image file is always undefined. What am I missing?

    function anotherFunc(text, imageFile){

      if (typeof imageFile == 'undefined'){
        console.log("image undefined")
      } else {
        console.log("Got image")
    }
 }

function theCaller(){
  var text ="hello"
  var imageFile = 'img.png'
  anotherFunc(text, imageFile)
}

This always outputs image undefined although I have the image in the same directory of the source code. I have also tried var imageFile = './img.png' but that does not help either.

Answer 1

if you'd like to test imageFile whether it's undefined or not you should do it like:

if (typeof imageFile == 'undefined'){
   console.log("image undefined")
  } else {
    console.log("Got image")
  }

Answer 2

You are only verifying that the string is not "undefined". Besides changing the code to correctly verify if it is undefined by either saying if (imageFile) or more explicitly if (typeof imageFile === 'undefined') you also need to actually provide an image and not just the text.

I would suggest you to do something like this:

const fs = require('fs');
const path = require('path');

let fileName = 'someName.png';
let fullPath = path.join(__dirname, 'some', 'path', fileName);

if (fs.existsSync(fullPath)) {
  let file = fs.readFileSync(fullPath);
  // do something with the file
}