The file read could be async, but your code fileReadCallBack will never be
called.
After fs.readFile(...) all the async magic take place, OK.
BUT YOUR JAVASCRIPT code will run the next command, after fs.readFile. It
is an infinite loop, becase fileReadCallBack will be called when your
JavaScript code free the JavaScript machine, so it can attend any callback
If you don't free the JavaScript machine, fileReadCallBack will never
executed, and your buffer will be empty for ever
Maybe better is
fs.readFile(process.argv[2], fileReadCallBack);
// Our callback function for our asyncronous file reading
function fileReadCallBack(err, data) {
if(err)
return; // or maybe better, inform the problem
var numOfNewLines = data.toString().split('\n').length-1;
console.log(numOfNewLines);
} }
Apologize my English ;-)
Angel "Java" Lopez
@ajlopez
On Sat, Jan 24, 2015 at 8:25 PM, Maverick Peppers <[email protected]>
wrote:
> // Start of program4 process
> var fs = require('fs');
>
> // Asyncronously read and send the buffer object of a file whose path
> // is set int 2nd argument of the process to the callback function.
> var buffer = 0;
> fs.readFile(process.argv[2], fileReadCallBack);
>
> while(buffer == 0) {}
>
> var numOfNewLines = buffer.toString().split('\n').length-1;
> console.log(numOfNewLines);
>
> // Our callback function for our asyncronous file reading
> function fileReadCallBack(err, data) { if(!err){ buffer = data; } }
>
> I'm using NodeSchool.io's workshop <http://nodeschool.io/#workshoppers>
> to learn Nodejs. I'm on problem 4, *Async File I/O *and the above code
> runs forever. If the file reading is asynchronous, I'm thinking *var
> buffer* should no longer be 0 and the while-loop will terminate and move
> on.
>
> I know the correct solution would place the logic inside of the callback
> function, but I'm curious as to why the code above doesn't work as expected.
>
> Thanks!
>
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