Return text file through HTTP request as an array javascript

Question

I ran into a roadblock when developing my website. I need it to pull a text file in the same directory and return each line as an array.

So I did my research and came up with a function that seemed simple enough. However when I alert(theArray); it returns as undefined. What am I doing wrong?

function pullText(x)
{
  var fullText = [];
  fileReturn=new XMLHttpRequest();
  fileReturn.onreadystatechange=function()
  {
    if (fileReturn.readyState==4 && fileReturn.status==200)
    {
      entireTextFile = fileReturn.responseText;
      // alert(entireTextFile); works as expected here
      lines = fileReturn.responseText.split("\n");
      // alert(lines); works as expected here
      fullText = lines;
    }
  }
  // alert(fullText); does not work.
  fileReturn.open("GET",x,true);
  fileReturn.send();
  return fullText;
}

Ja͢ck · Accepted Answer · 2013-03-14 18:20:29Z

2

It won't work that way because AJAX is A-synchronous. You should pass a callback handler and call that once the document is ready.

function pullText(x, callback)
{
//      var fullText = []; not necessary
  fileReturn=new XMLHttpRequest();
  fileReturn.onreadystatechange=function()
  {
    if (fileReturn.readyState==4 && fileReturn.status==200)
    {
      entireTextFile = fileReturn.responseText;
      // alert(entireTextFile); works as expected here
      lines = fileReturn.responseText.split("\n");
      // alert(lines); works as expected here
      callback(lines);
    }
  }
  // alert(fullText); does not work.
  fileReturn.open("GET",x,true);
  fileReturn.send();
}

pullText(whatever, function(lines) {
    // use lines here
});

answered Mar 14, 2013 at 18:20

Ja͢ck

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