Whenever you want to use the data retrieved from ajax, you must use it in the callback function which is triggered when the ajax call receives the response. This is a common practice.
But if the ajax call to retrieve data resides in a common function, it would be a little more complicated. Below I give an example to explain this.
function DataUtil(callBack) {
var me = this;
$.ajax({
url : "../json/test.json",
success : function(data) {
me.data = $.parseJSON(data);
callBack(me);
}
});
// can only be used in the callBack
me.getName = function() {
return me.data.name;
};
// can only be used in the callBack
me.getDescription = function() {
return me.data.description;
};
}
function displayRetrievedData() {
var dataRetrieved = {};
var callBack = function(dataUtil) {
dataRetrieved.name = dataUtil.getName();
dataRetrieved.description = dataUtil.getDescription();
console.log("in the call back:");
console.log(dataRetrieved);// gets the correct data from the json
};
DataUtil(callBack);
console.log("out the call back:");
console.log(dataRetrieved);// not sure it gets the data from the json. It
// depends the ajax call speed
}
function canNotGetCorrectData() {
var dataRetrieved = {};
var dataUtil = new DataUtil(function() {
});
dataRetrieved.name = dataUtil.getName();// not sure the data is ready
dataRetrieved.description = dataUtil.getDescription();// not sure the data is ready
console.log("Can not get the data:");
console.log(dataRetrieved);
}
displayRetrievedData();
canNotGetCorrectData();
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