fs.readFile Function Response is undefined... Any Ideas?

Question

Im running a simple readfile command, for a video tutorial, and this is the code exactly as the instructor saved it...

var fs = require("fs");
console.log("Starting");
fs.readFile("./sample.txt", function(error, data) {
console.log("Contents: " + data);
});
console.log("Carry on executing");

i have the sample.txt in the same folder as this js file, and in the sample.txt file i have "This is a sample output for this text document", unfortunately i get a "undefined" as the output for the data variable in the code.

If anybody has any insight as to why this is happening, it would be wonderful if someone would help....

THANKS

Answer 1

Try checking if the file exists first:

var fs = require("fs");
console.log("Starting");

fs.exists("./sample.txt", function(fileok){
  if(fileok)fs.readFile("./sample.txt", function(error, data) {
    console.log("Contents: " + data);
  });
  else console.log("file not found");
});
console.log("Carry on executing");

If it doesn't exists, check the path, filename and extension, because your code is OK.

Answer 2

Depending on where you are running this from, the root at which ./sample.txt gets resolved may vary.

To ensure, that it resolves relative to your module, do the following:

var fs = require("fs");
var path = require('path');

var sampleTxt = path.join(__dirname, 'sample.txt');

console.log("Starting");
fs.readFile(sampleTxt, function(error, data) {
  if (error) return console.error(error);
  console.log("Contents: " + data);
});
console.log("Carry on executing");