Cant access array elements outside a function

Question

I am trying to hash the name together with the path of all the files from a specific directory. After hashing I am saving the hash into the array(hash_orig). Here is what I have done.

var fs = require('fs');
var Hashes = require('jshashes');
var path = process.argv[2];
var path_elements = new Array();
var hash_orig = new Array();


fs.readdir(path, function(err, items) {
console.log('\nNumber of files in the directory: '+items.length);
console.log('Hashing algorithm: SHA1')
    for (var i=0; i<items.length; i++) {
        path_elements.push(path+"/"+items[i])
        var SHA1 = new Hashes.SHA1().b64(path_elements[i])
        console.log([i+1]+':\t'+items[i]+"\t" + SHA1)
        hash_orig.push(SHA1);
    }
});

    console.log(hash_orig)

The problem:

The problem is that when I am pushing the hash into the hash_orig array and trying to access it outside the function fs.readdir the array hash_orig is empty. (console.log(hash_orig))

I need to access it outside in order to perform further some comparison operation to determine if the hash has been changed to Verifying Integrity of the files name and path. What I am doing wrong? Thank you.

PatrickD · Accepted Answer · 2015-10-11 16:10:01Z

4

fs.readdiris a async function. At the time when console.log(hash_orig)is reached, the callback of readdir is not called yet. Put the log-statement at the end of your callback and you will see the results.

answered Oct 11, 2015 at 16:10

PatrickD

1,1565 silver badges7 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Rémi Becheras · Accepted Answer · 2015-10-11 16:13:49Z

1

Yes you are simply missing that your fs.readdir function is a asynchronous callback.

Thus, when you call console.log(hash_orig), from outside, in fact the callback isnt completed yet.

Use a timeout and your array will filled :

setTimeout(function(){
  console.log(hash_orig);
},500);

answered Oct 11, 2015 at 16:13

Rémi Becheras

15.3k14 gold badges55 silver badges85 bronze badges

Collectives™ on Stack Overflow

Cant access array elements outside a function

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related