var myfunction = function(){
$('.menu').delay(3000).slideDown("fast").attr('style', 'color:#fff')
return false;
});
Can i repeat myfunction exclude delay(3000)?
Means something like $('#submit').click(myfunction); but myfunction should exclude .delay(3000)
Set your function up with a variable for time:
var myfunction = function(delayTime) {
$('.menu').delay(delayTime).slideDown("fast").attr('style', 'color:#fff')
return false;
});
Then call it with the time value as an argument:
myfunction(3000);
or
myfunction(0);
In cases like this, I like to create a curried function (that is, a function that returns a function).
function myFunction(doDelay){
return function(){
$('.menu').delay(doDelay ? 3000 : 0).slideDown('fast') //...
return false
}
}
Then you could set up your click listener like
$('#submit').click(myFunction(false))
And call it with the delay like myFunction(true)(), or create different delayed instances like var myFunctionDelayed = myFunction(true) or var myFunctionNoDelay = myFunction(false)
Related
I have an API that takes a function as an input, and then inside the API, the intent is to add the function to an Array if the function is not already added to the Array.
The call to the API is of the form:
myApiHandle.addIfUnique(function(){
myResource.get(myObj);
});
The API is:
myApiHandle.addIfUnique(myFunc) {
if (myArray.indexOf(myFunc) === -1) {
return;
}
// add to array
}
Now this obviously does not work as expected, since each time a new function is being passed in.
My Question is: Is there a way to pass in a function into the myApiHandle.addIfUnique call that will allow me to compare the existing functions in the array with this function that is currently passed in? The comparison should compare the function name and the object, and if both are the same, then not add the function to the array. I want to avoid adding another argument to the addIfUnique call if at all possible.
In other words, is the below possible:
myApiCall.addIfUnique (someFunc) {
}
If so, what is the someFunc. And what would be the logic inside the API to detect if the function already exists in myArray?
The same problem occurs with addEventListener and removeEventListener, where the callback must be identical (in the === sense) for removeEventListener to remove it.
As you've found, obviously if you call addIfUnique like this:
addIfUnique(function() { })
the function passed each time will be a unique object. The solution is to create the function once:
var fn = function() { };
addIfUnique(fn);
addIfUnique(fn);
A related problem occurs when the function being passed in is a method invocation, so I need to bind it:
var x = { val: 42, method: function() { console.log(this.val); } };
I want to pass a bound version of it, so
addIfUnique(x.method.bind(x));
addIfUnique(x.method.bind(x));
But again, each call to x.method.bind(x) will return a separate function. So I need to pre-bind:
var boundMethod = x.method.bind(x);
addIfUnique(boundMethod);
addIfUnique(boundMethod);
First of all, comparing functions is meaningless, even if two functions are literally different, they may be functionally the same.
And for your problem, you can compare whether it's exactly the same object, or you can compare it literally by using toString() function and regExp.
var addIfUnique = (function() {
var arr = [];
return function(func) {
if (~arr.indexOf(func)) return false;
var nameArr = [];
var funcName = func.name;
var funcRegExp = new RegExp('[^\{]+\{(.+)\}$', 'i');
var funcStr = func.toString().match(funcRegExp);
funcStr = funcStr && funcStr[1];
if (!funcStr) return false;
var strArr = arr.map(function(v){
nameArr.push(v.name);
return v.toString().match(funcRegExp)[1];
});
if (~strArr.indexOf(funcStr) && ~nameArr.indexOf(funcName)) return false;
arr.push(func);
};
}());
I got below a Jquery function to switch between two buttons simultaneously but it's a "dirty" way of writing the code my boss will say. I don't wanna call the functions or no passing in Jquery parameter, is the there a simple or better way to write this function since i'm totally new to programming?
Below the Jquery
var startStopBtn = function () {
var startBtn = $('#timerStart');
var stopBtn = $('#timerStop').hide();
var Start = function () {
startBtn.hide();
stopBtn.show();
};
var Stop = function () {
var remarks2 = $(".textArea-one").val();
if (remarks2 !== "") {
startBtn.show();
stopBtn.hide();
}
};
return {
Start: Start,
Stop: Stop
};
}(jQuery);
jQuery('#timerStart').on('click', startStopBtn.Start);
jQuery('#timerStop').on('click', startStopBtn.Stop);
I think code could be done in many ways, this is just one of them.
Looks like first you want to hide the stopBtn so create a function to do this. Call that function on page load or create a funtion and call it when the page loads. Here I create a function that you should call whenever you want. If you don't want to do that, just delete that function.
Then make two diferent functions that are done when you "click" #timerStart or #timerStop.
This is my version but i'm sure it can be improved:
function startStopBtn(){
$('#timerStop').hide();
};
$('#timerStart').on('click', function(){
$('#timerStart').hide();
$('#timerStop').show();
});
$('#timerStop').on('click', function(){
var remarks2 = $(".textArea-one").val();
if (remarks2 !== "") {
$('#timerStart').show();
$('#timerStop').hide();
}
});
I have tried different things but I do seem to be looking something over that is too obvious. Trying to use the value a function(method) returns inside an object and use it in another method with setTimeout within that same object.
This is the html:
<h1>3000</h1>
The javascript (jQuery in this case):
var foo = {
getValue: function() {
var h1Text = $('h1').text();
h1Text = parseInt(h1Text);
return h1Text;
},
useValue: function() {
var time = this.getValue();
var alertIt = alert('Hello');
setTimeout(alertIt,time);
}
};
foo.useValue();
// log shows correct value
console.log(foo.getValue());
// returns a number
console.log(typeof(foo.getValue()));
The alert does show up, but on load rather than using those 3 seconds.
It does log the correct value and also says it's a number so I'm really not sure what I am doing wrong. Any help is appreciated. Thanks
In useValue() you call alert('Hello'), so it's executed immediately and the result is stored in alertIt variable. You should put it inside the function like this, as setTimeout expects a function as a first parameter:
var alertIt = function() {
alert('Hello');
}
setTimeout(alertIt,time);
setTiimeout expects function and not variable.
Also var alertIt = alert('Hello'); this will return undefined.
Note: var a = function() will call it and assign return value. To assign a function to a variable with parameter, use .bind
Try alert.bind(null, "hello");
For demo purpose, I have hardcoded value of delay and commented getValue code.
var foo = {
getValue: function() {
//var h1Text = $('h1').text();
//h1Text = parseInt(h1Text);
return true// h1Text;
},
useValue: function() {
var time = 3000//this.getValue();
var alertIt = alert.bind(null,'Hello');
setTimeout(alertIt, time);
}
};
foo.useValue();
// log shows correct value
console.log(foo.getValue());
// returns a number
console.log(typeof(foo.getValue()));
First of all excuse for my weak english, I try to use the following javascript code and I want to return id variable and use it in other function, but it seem does not work correctly and does not return it, can someone help me out writting this
var idcb = $('.box').click(function() {
var id = $(this).attr('id');
return id;
});
I want to use var idcb in this function :
$(".hs").click(function() {
$(idhs).slideToggle("slow");
return false;
});
});
for that to work, the jquery click implementation would need to know that the function you pass it returns a value, and that it itself should return that value - which isn't the case.
instead, you could use some closure magic to do this easily. try this:
var idcb;
$('.box').click(function() {
idcb = $(this).attr('id');
});
You are passing an anonymous function to an event handler, you cannot return a value from this type of function. The solution is to use closures to get around this :
var idcb = null;
$('.box').click(function() {
idcb = $(this).attr('id');
});
The variable idcb will always be set to the id of the last .box that was clicked.
The function is given as a parameter to the click function and is run asynchronously when the user clicks on an element. So you can't return a value directly, since the function won't be run immediately. You can look up the id value another way, or pass it to a function to work with instead of returning it, or just do this:
var idcb = $('.box').click(function() {
var id = $(this).attr('id');
$(id).slideToggle("slow");
});
You cannot do it the way you are trying to. However, what you can do is use a variable that is accessible by both functions to share values between them.
var icdb = 'test';
function a() {
icdb = 'another value';
}
function b() {
console.log(icdb);
}
a();
b();
You could also call b from a and pass the variable as argument:
function a() {
b('test');
}
function b(icdb) {
console.log(icdb);
}
a();
your variable idcb contains the click handler !
you need to declare the vriable outside the handler and assign to it inside to make this work:
var idcb = null;
// ... whatever
$('.box').click(function() {
idcb = $(this).attr('id');
return true; // return 'true' from an event handler to indicate successful completion
});
Check this out
var id=null;
$('.box').click(function() {
id = $(this).attr("id");
});
$(".hs").click(function() {
$("#"+id).slideToggle("slow");
return false;
});
You could pass in the an object as a reference to the click function
and change the value from the callback. Another option is using closures
The caveat to this jsfiddle is that you have to call a .box element first.
http://jsfiddle.net/D6B73/2/
var idcb = {};
$('.box').click(idcb, function (event) {
event.data.value = $(this).attr('id');
console.log(idcb.value);
});
$('.hs').click(function() {
$('#'+idbc.value).slideToggle("slow");
});
You can do it this way:
$(".hs").on('click', function() {
var id = $('.box').attr('id');
alert(id);
});
I'm writing a little plugin for jQuery and so far I've got this:
(function($){
$.fn.extend({
someFunction: function() {
return this.each(function() {
var obj = $(this);
obj.focus(someInternalFunction(obj));
});
}
});
function someInternalFunction(obj) {
};
})(jQuery);
The problem is, when i attach someFunction to the object, the object gets focus and binding of someInternalFunction on focus event fails.
Then I tried to bind function to wrap the function call in the other function:
obj.focus(function() {
someInternalFunction($(this));
});
This code works, but it isn't pretty at all. Is it possible to bind function on focus without wrapping it in the other function?
$.fn.bindFocus() = function(){
var internalFunction = function(){
var $this = $(this),
self = this;
// try do stuff here
};
return this.each(function(){
$(this).bind('focus', internalFunction);
});
}
$('#myElement').bindFocus();
Hope it'll help ?
EDT. Sorry, first time get you wrong :)
Here:
obj.focus(someInternalFunction(obj));
^^^^^
... you're calling the function, meaning that its return value is the thing that actually ends up being passed to focus(). Instead you want to pass a function to focus(). Given the fact that you want to pass obj to someInternalFunction, you'll have to define an additional function to wrap it all:
obj.focus(function(){
someInternalFunction(obj);
});
Just to make things clear:
var x = function() { return 3; }; // Defining a function
x; // -> this is a function reference
x(); // -> this is 3