frdl.when
- Asynchronous PromiseAus der Kategorie: Resources
window.frdl.when
function(condition, _then, withMe, _or, delayed, initFn)
Checks a given scope for a specificcondition(by condition || function) repeatedly within a configurable interval and triggers athenableif the condition evaluates to true by calling a givencallbackfunction applying a given scope variable as argument. The returned Promise provides a ["magic function"].__call(name, args) to provide some kind of "overloading".
@returnsinstanceofPromise
Example
The following snippet triggers an alert and resolves to true if the name of the window changes (checks for the change every 1 microsecond and should trigger after 5 seconds).
var NumChecks = -1;
var oldWindowName = window.name;
var AlteredWindowName = frdl.when(function(wn){
NumChecks++;
return (wn !== oldWindowName || oldWindowName !== window.name) ? true : false;
}, function(wn){
alert('The window.name changed from "'+oldWindowName+'" to "'+window.name+'"!');
return true;
}, window.name, function(wn){
console.warn('Error oberving window.name.onchange thenable in frdl.when! '
+ oldWindowName + ' to '+wn);
return false;
}, 1, function(wn){
NumChecks++;
setTimeout(function(){
/**
* Our init function changes the window.name
* after some seconds to make the when happen for our test!
*/
window.name = oldWindowName + ' checked ' + NumChecks + ' times';
},5000);
});
Core
/**
* if delayed is a function, delayed is the initial Function
* if delayed AND initFn are functions, delayed is the initial function and initFn is called each iteration of check(condition) function
* if initFn is a function and delayed is NOT a function, initFn is the initial Function
* otherwise there is no initial function or additional check(condition) function
*
* promise resolves if condition is true
* promise rejects if condition is undefined || null
*
* condition should be either a function or boolean expression
*/
_.when=function(condition, _then, withMe, _or, delayed /* !isNaN || typeof function */, initFn /* typeof function || undefined */){
if('function'===typeof delayed && 'function'!==typeof initFn){
var init = delayed;
delayed=(isNaN(initFn)) ? 1 : initFn;
} else if ('function'===typeof delayed && 'function'===typeof initFn){
var fN = initFn;
var init = new delayed;
delayed = 1;
} else if( 'function'===typeof initFn){
var init = initFn;
}
var check = function(condition, me){
if('function'===typeof fN)fN(me);
return ( ( 'function'===typeof condition && true === condition(me) )
|| (true === (condition))
) ? true : condition;
};
if('function'===typeof init){
init(withMe);
}
delayed=(isNaN(delayed)) ? 1 : delayed;
if(true===check(condition, withMe))return _then(withMe);
var p = new Promise(function(resolve, reject){
function h() {
var c = check(condition, withMe);
if (true===c) {
resolve(withMe);
/* } else if (false!==c && true!==c) { */
} else if (undefined===c || null ===c) {
reject(withMe);
}else{
setTimeout(function(){
h();
},(delayed || 1));
}
}
h();
});
p.then(function(withMe) {
return _then(withMe);
}, function(withMe) {
return _or(withMe);
});
var rProxy = _.overload(p, function(name, args){
if('function'===typeof withMe[name]){
return withMe[name](Array.prototype.slice.call(args));
}else{
setTimeout(function(){
rProxy.__call(name, args);
},1000);
}
});
return rProxy;
};
Erstellt vonWEBFAN(Monday 1st of August 2016 09:04:07 AM - vor995.65Tagen)
in der KategorieResourcesals statische Seite
Zuletzt geändert: Monday 1st of August 2016 10:01:30 AM vonWEBFAN
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