How should I call 3 functions in order to execute

2019-01-01 10:02发布

If I need call this functions one after other,

        $('#art1').animate({'width':'1000px'},1000);        
        $('#art2').animate({'width':'1000px'},1000);        
        $('#art3').animate({'width':'1000px'},1000);        

I know in jQuery I could do something like:

        $('#art1').animate({'width':'1000px'},1000,'linear',function(){
            $('#art2').animate({'width':'1000px'},1000,'linear',function(){
                $('#art3').animate({'width':'1000px'},1000);        
            });        
        });        

But, let's assume that I'm not using jQuery and I want to call:

        some_3secs_function(some_value);        
        some_5secs_function(some_value);        
        some_8secs_function(some_value);        

How I should call this functions in order to execute some_3secs_function, and AFTER that call ends, then execute some_5secs_function and AFTER that call ends, then call some_8secs_function?

UPDATE:

This still not working:

    (function(callback){
        $('#art1').animate({'width':'1000px'},1000);
        callback();
    })((function(callback2){
        $('#art2').animate({'width':'1000px'},1000);
        callback2();
    })(function(){
        $('#art3').animate({'width':'1000px'},1000);
    }));

Three animations start at same time

Where is my mistake.

10条回答
浅入江南
2楼-- · 2019-01-01 10:15

Since you tagged it with javascript, I would go with a timer control since your function names are 3, 5, and 8 seconds. So start your timer, 3 seconds in, call the first, 5 seconds in call the second, 8 seconds in call the third, then when it's done, stop the timer.

Normally in Javascript what you have is correct for the functions are running one after another, but since it looks like you're trying to do timed animation, a timer would be your best bet.

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低头抚发
3楼-- · 2019-01-01 10:15

I use a 'waitUntil' function based on javascript's setTimeout

/*
    funcCond : function to call to check whether a condition is true
    readyAction : function to call when the condition was true
    checkInterval : interval to poll <optional>
    timeout : timeout until the setTimeout should stop polling (not 100% accurate. It was accurate enough for my code, but if you need exact milliseconds, please refrain from using Date <optional>
    timeoutfunc : function to call on timeout <optional>
*/
function waitUntil(funcCond, readyAction, checkInterval, timeout, timeoutfunc) {
    if (checkInterval == null) {
        checkInterval = 100; // checkinterval of 100ms by default
    }
    var start = +new Date(); // use the + to convert it to a number immediatly
    if (timeout == null) {
        timeout = Number.POSITIVE_INFINITY; // no timeout by default
    }
    var checkFunc = function() {
        var end = +new Date(); // rough timeout estimations by default

        if (end-start > timeout) {
            if (timeoutfunc){ // if timeout function was defined
                timeoutfunc(); // call timeout function
            }
        } else {
            if(funcCond()) { // if condition was met
                readyAction(); // perform ready action function
            } else {
                setTimeout(checkFunc, checkInterval); // else re-iterate
            }
        }
    };
    checkFunc(); // start check function initially
};

This would work perfectly if your functions set a certain condition to true, which you would be able to poll. Plus it comes with timeouts, which offers you alternatives in case your function failed to do something (even within time-range. Think about user feedback!)

eg

doSomething();
waitUntil(function() { return doSomething_value===1;}, doSomethingElse);
waitUntil(function() { return doSomethingElse_value===1;}, doSomethingUseful);

Notes

Date causes rough timeout estimates. For greater precision, switch to functions such as console.time(). Do take note that Date offers greater cross-browser and legacy support. If you don't need exact millisecond measurements; don't bother, or, alternatively, wrap it, and offer console.time() when the browser supports it

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旧人旧事旧时光
4楼-- · 2019-01-01 10:16

your functions should take a callback function, that gets called when it finishes.

function fone(callback){
...do something...
callback.apply(this,[]);

}

function ftwo(callback){
...do something...
callback.apply(this,[]);
}

then usage would be like:

fone(function(){
  ftwo(function(){
   ..ftwo done...
  })
});
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深知你不懂我心
5楼-- · 2019-01-01 10:17

You could also use promises in this way:

    some_3secs_function(this.some_value).then(function(){
       some_5secs_function(this.some_other_value).then(function(){
          some_8secs_function(this.some_other_other_value);
       });
    });

You would have to make some_value global in order to access it from inside the .then

Alternatively, from the outer function you could return the value the inner function would use, like so:

    one(some_value).then(function(return_of_one){
       two(return_of_one).then(function(return_of_two){
          three(return_of_two);
       });
    });
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听够珍惜
6楼-- · 2019-01-01 10:21
asec=1000; 

setTimeout('some_3secs_function("somevalue")',asec*3);
setTimeout('some_5secs_function("somevalue")',asec*5);
setTimeout('some_8secs_function("somevalue")',asec*8);

I won't go into a deep discussion of setTimeout here, but:

  • in this case I've added the code to execute as a string. this is the simplest way to pass a var into your setTimeout-ed function, but purists will complain.
  • you can also pass a function name without quotes, but no variable can be passed.
  • your code does not wait for setTimeout to trigger.
  • This one can be hard to get your head around at first: because of the previous point, if you pass a variable from your calling function, that variable will not exist anymore by the time the timeout triggers - the calling function will have executed and it's vars gone.
  • I have been known to use anonymous functions to get around all this, but there could well be a better way,
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步步皆殇っ
7楼-- · 2019-01-01 10:26

This answer uses promises, a JavaScript feature of the ECMAScript 6 standard. If your target platform does not support promises, polyfill it with PromiseJs.

Look at my answer here Wait till a Function with animations is finished until running another Function if you want to use jQuery animations.

Here is what your code would look like with ES6 Promises and jQuery animations.

Promise.resolve($('#art1').animate({ 'width': '1000px' }, 1000).promise()).then(function(){
    return Promise.resolve($('#art2').animate({ 'width': '1000px' }, 1000).promise());
}).then(function(){
    return Promise.resolve($('#art3').animate({ 'width': '1000px' }, 1000).promise());
});

Normal methods can also be wrapped in Promises.

new Promise(function(fulfill, reject){
    //do something for 5 seconds
    fulfill(result);
}).then(function(result){
    return new Promise(function(fulfill, reject){
        //do something for 5 seconds
        fulfill(result);
    });
}).then(function(result){
    return new Promise(function(fulfill, reject){
        //do something for 8 seconds
        fulfill(result);
    });
}).then(function(result){
    //do something with the result
});

The then method is executed as soon as the Promise finished. Normally, the return value of the function passed to then is passed to the next one as result.

But if a Promise is returned, the next then function waits until the Promise finished executing and receives the results of it (the value that is passed to fulfill).

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