closures

问题 Code belongs to javascriptissexy.com My question is why invoking mjName ("Jackson") returns "This celebrity is Michael Jackson"? Is it that second parameter given in ANY outer function always, says to js = inner function parameter? Could someone explain the whole concept in great detail? function celebrityName (firstName) { var nameIntro = "This celebrity is "; // this inner function has access to the outer function's variables, including the parameter function lastName (theLastName) { return

问题 I am working on a web page that uses dojo and has a number (6 in my test case, but variable in general) of project widgets on it. I'm invoking dojo.addOnLoad(init), and in my init() function I have these lines: dojo.connect(dijit.byId("project" + 0).InputNode, "onChange", function() {makeMatch(0);}); dojo.connect(dijit.byId("project" + 1).InputNode, "onChange", function() {makeMatch(1);}); dojo.connect(dijit.byId("project" + 2).InputNode, "onChange", function() {makeMatch(2);}); dojo.connect

问题 I'm having a little difficulty with the inherent concept of a closure. I get the basic idea, but here's the thing: I thought that, technically, there "is a closure" inside every Javascript function. To quote wikipedia: In computer science, a closure (also lexical closure, function closure or function value) is a function together with a referencing environment for the nonlocal names (free variables) of that function. Such a function is said to be "closed over" its free variables. So since you

问题 Suppose I'm using Swift and calling a method in the framework that is expecting a delegate. Is it possible to provide a closure and implement the delegate right there inline? I'm hoping to be able to use this like anonymous classes in Java. For Example: let cnx:NSURLConnection = NSURLConnection(request: request, delegate: { func connection(connection: NSURLConnection!, didReceiveData data: NSData!){ //append data } func connectionDidFinishLoading(connection: NSURLConnection){ //all done } });

问题 Today I am trying to make a store locator using google maps' api. The store locator is to be set up like so: two areas, one with a map containing all the stores in a given area (measured in a selectable radius from a center point), and one area with a list of all the stores on the map, their information, and of course a link to their website. When a person clicks on the name of the store on the store list, it centers upon the store in the map, and opens an infoWindow above the store marker. I

问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 6 years ago . I am trying to settle on a method that will provide me the most elegant way of wrapping my code in Namespace / Unit like objects. For

问题 What's the best way to access my this.rules variable from within $.each()? Any explanation of why/how would also be helpful! app.Style = function(node) { this.style = node; this.rules = []; var ruleHolder = node.find('Rule'); $.each(ruleHolder, function(index, value) { var myRule = new app.Rule($(ruleHolder[index])); this.rules.push(myRule); }); console.log(this.rules) } 回答1: Store a reference to this -- name it self , for example --, before calling .each() , and then access rules using self

问题 What's the best way to access my this.rules variable from within $.each()? Any explanation of why/how would also be helpful! app.Style = function(node) { this.style = node; this.rules = []; var ruleHolder = node.find('Rule'); $.each(ruleHolder, function(index, value) { var myRule = new app.Rule($(ruleHolder[index])); this.rules.push(myRule); }); console.log(this.rules) } 回答1: Store a reference to this -- name it self , for example --, before calling .each() , and then access rules using self

问题 The Akka documentation is documenting dangerous variants of using Props : // NOT RECOMMENDED within another actor: // encourages to close over enclosing class val props7 = Props(new MyActor) Then carries on stating: This method is not recommended to be used within another actor because it encourages to close over the enclosing scope, resulting in non-serializable Props and possibly race conditions (breaking the actor encapsulation). Could someone please explain the meaning of "closing over

问题 Like the following codes: var foo = function() { var a = 1; // closure var return function() { // closure fun console.log(a); } }; var bar = foo(); When foo exits(or say, returns), we know that the variable a will not be destroyed and remains in memory(that's why closure works). So my problem is where does the the variable a store, stack or heap? 回答1: A closure is just an evolution of the concept of the stack. The stack is used to separate/isolate scope when functions are called. When a