I need a bunch of functions to be called in strict order. It's also very important that the next function waits until the previous one has finished.
Right now I'm using chained callbacks:
callMe1(function(){
callMe2(function(){
开发者_运维技巧 callMe3(function(){
callMeFinal();
});
});
});
This works but seems to be a little ugly.
Any suggestions for a different approach?
If you use jQuery, then you can use queue
to chain the functions.
$(document)
.queue(callMe1)
.queue(callMe2);
where callMeX
should be of form:
function callMeX(next) {
// do stuff
next();
}
You can implement a "stack" system:
var calls = [];
function executeNext(next) {
if(calls.length == 0) return;
var fnc = calls.pop();
fnc();
if(next) {
executeNext(true);
}
}
/*To call method chain synchronously*/
calls.push(callMe3);
calls.push(callMe2);
calls.push(callMe1);
executeNext(true);
/*To call method chain asynchronously*/
calls.push(callMe3);
calls.push(function(){
callMe2();
executeNext(false);
});
calls.push(function(){
callMe1();
executeNext(false);
});
Not sure if this would help you, but there is a great article on using deferreds in jQuery 1.5. It might clean up your chain a bit...
Also, my answer on Can somebody explain jQuery queue to me has some examples of using a queue for ensuring sequential calls.
You might want to pass parameters to the functions, I do not believe you can at the time of this writing. However...
function callMe1(next) {
console.log(this.x);
console.log("arguments=");
console.log(arguments);
console.log("/funct 1");
this.x++;
next();
}
function callMe2(next) {
console.log(this.x);
console.log("arguments=");
console.log(arguments);
console.log("/funct 2");
this.x++;
next();
}
function callMe3(next) {
console.log(this.x);
console.log("arguments=");
console.log(arguments);
console.log("/funct 3");
this.x++;
next();
}
var someObject = ({x:1});
$(someObject).queue(callMe1).queue(callMe2).queue(callMe3);
Wrapping your functions, arguments intact, with an anonymous function that plays along with .queue
works too.
Passing Arguments in Jquery.Queue()
var logger = function(str, callback){
console.log(str);
//anything can go in here, but here's a timer to demonstrate async
window.setTimeout(callback,1000)
}
$(document)
.queue(function(next){logger("Hi",next);})
.queue(function(next){logger("there,",next);})
.queue(function(next){logger("home",next);})
.queue(function(next){logger("planet!",next);});
Example on JSFiddle: http://jsfiddle.net/rS4y4/
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