Ember.js- define a global function that can return a value to actions

The code below shows a standard JavaScript pattern for defining a function that takes a number of bytes and converts it into a readable format.

In standard JavaScript, you can call the function as a variable, so that the variable value is whatever the function returns.

//Define function
function bytesToReadable(numberOfBytes) {
  var readableSize;
  var units;
  if (numberOfBytes <= 1000) {
    readableSize = numberOfBytes;
    units = ' bytes';
  } else if (numberOfBytes > 1000 && numberOfBytes <= 1000000) {
    readableSize = Math.ceil(numberOfBytes / 1000);
    units = ' KB';
  } else if (numberOfBytes > 1000000 && numberOfBytes <= 1000000000) {
    readableSize = (numberOfBytes / 1000000).toFixed(2);
    units = ' MB';
  } else if (numberOfBytes > 1000000000 && numberOfBytes <= 1000000000000) {
    readableSize = Math.ceil(numberOfBytes / 1000000000);
    units = ' GB';
  }
  var prettySize = readableSize + units;
  return prettySize;
}
//Call function
var test = bytesToReadable(2360000);
console.log(test);//Logs '2.36MB'

What is the correct way of achieving this type of pattern in Ember?

I have tried placing the code in it's own action as below, but this returns undefined:

---

actions: {
  bytesToReadable: function(numberOfBytes) {
    var readableSize;
    var units;
    if (numberOfBytes <= 1000) {
      readableSize = numberOfBytes;
      units = ' bytes';
    } else if (numberOfBytes > 1000 && numberOfBytes <= 1000000) {
      readableSize = Math.ceil(numberOfBytes / 1000);
      units = ' KB';
    } else if (numberOfBytes > 1000000 && numberOfBytes <= 1000000000) {
      readableSize = (numberOfBytes / 1000000).toFixed(2);
      units = ' MB';
    } else if (numberOfBytes > 1000000000 && numberOfBytes <= 1000000000000) {
      readableSize = Math.ceil(numberOfBytes / 1000000000);
      units = ' GB';
    }
    var prettySize = readableSize + units;
    return prettySize;
  },

  anotherAction: function() {
    var test = this.send('bytesToReadable', 2360000);
    console.log(test) //Logs undefined.
  },
}

I have also tried using properties:

bytesToReadable: function(numberOfBytes) {
    var readableSize;
    var units;
    if (numberOfBytes <= 1000) {
      readableSize = numberOfBytes;
      units = ' bytes';
    } else if (numberOfBytes > 1000 && numberOfBytes <= 1000000) {
      readableSize = Math.ceil(numberOfBytes / 1000);
      units = ' KB';
    } else if (numberOfBytes > 1000000 && numberOfBytes <= 1000000000) {
      readableSize = (numberOfBytes / 1000000).toFixed(2);
      units = ' MB';
    } else if (numberOfBytes > 1000000000 && numberOfBytes <= 1000000000000) {
      readableSize = Math.ceil(numberOfBytes / 1000000000);
      units = ' GB';
    }
    var prettySize = readableSize + units;
    return prettySize;
  },
  actions: {
    anotherAction: function() {
      var test = this.get('bytesToReadable', 2360000);
      console.log(test);//Logs the function itself.
    },
  }

I would like to be able to run this code from various different parts of my application. What is the best way to make such a function available throughout my app, so that it can return the result to the function it has been called from?