I use the $.get() function to process a lot of files and I need to find out the filename I am calling with from within its callback function. is there a way to do this?
while (allFilesToImport.length > 0) {
var fileToOperate = allFilesToImport.shift();
var jqxhr = $.get(path + '/' + fileToOperate,
function(data, textStatus, jqXHR){ // here I need the fileToOperate variable!});
You can access fileToOperate and mypathToTheFile inside your function - that's one of the reasons why closures are awesome.
Here's an example with a loop in case that's what you have:
var filenames = ['a', 'b', 'c'];
for(var i = 0; i < filenames.length; i++) {
(function(filename) {
$.get('whatever/'+filename, function(data) {
// here you can use filename and it will point to the correct value
});
})(filenames[i]);
}
You could also use $.each() to iterate over the array:
$.each(filenames, function(i, filename) {
$.get('whatever/'+filename, function(data) {
// here you can use filename and it will point to the correct value
});
});
Just use this variable inside callback function. It will grab variable's value from outer scope.
var mypathToTheFile = path + '/' + fileToOperate;
var jqxhr = $.get(mypathToTheFile, function(data, textStatus){
// here I need the mypathToTheFile variable!
do_something(mypathToTheFile);
});
There a simple solution to that. JAvaScript supports closures, meaning you can use variables from outside the function scope inside the function value you pass to $.get as a callback (and everywhere else where you pass a function value)
var mypathToTheFile = path + '/' + fileToOperate;
var jqxhr = $.get(mypathToTheFile,
function(data, textStatus){
// here you simply use the mypathToTheFile variable!
});
There are some oddities to be aware of when you use closures. Anychanges to the variable outside the function scope will be reflected inside the function. E.g
var functionValues = [],i,j;
for(i=0;i<10;i+=1){
j = new String(i);
functionValues[i] = function(){alert(j);};
}
for(i=0;i<10;i+=1){
functionValues[i](); //this will alert 9 every time
}
will alert 9 10 times and not as you might expect 0,1,2,3,4,5,6,7,8,9
XMLHTTPRequestobject: api.jquery.com/jQuery.get/#jqxhr-object