callback

问题 Basic use case. I have a global variable where I store remotely pulled data. If there is no data then I want to load it initially, wait for it load, and then continue processing. I don't really want to use a synchronous process if I don't have to. Consider something like this where _companies is a global variable... if (_companies === undefined || _companies.length == 0) { loadExternalData(); } // do something with the data in _companies I feel like I'm missing something obvious. I understand

问题 Closed . This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 3 years ago . What is the correct way to call the same function on an array of objects using callbacks to advance? Essentially processing asynchronous calls sequentially. doAsynchFunction(data,callback){ console.log(data); wait(1000,callback); // do something that takes some time and execute callback } var a=[1

问题 I'm using OpenCV in python on OSX(10.10.5). I'm just starting out, so I may have made a silly mistake here. However, I haven't found anything that addresses this issue. I have a mouse callback function that makes a list containing the coordinates of each point that is clicked on in a loaded image. Now I'd like to use the flags in the mouse callback function to control whether I append coordinates to the list or whether I instead append "NA,NA" (e.g. if a point is missing from an image, I

问题 I'm trying my damndest to avoid callback hell with my Node JS. But I'm trying to make a large number of api-requests and insert these into my database. My issue here (of course) is that my for-loop runs and increments i before I finish my request and database insertion. for(var i = 0; i <= 1 ; i++){ apiRequest = data[i]; apicall(apiRequest); } function apicall(urlApi){ request((urlApi), function(error, response, body){ if(error){ console.log("error"); } else if(!error && response.statusCode =

问题 Hi there I am really stuck on this and since I am a javscript beginner this boggles my mind. Is there someone who knows how to write the following javascript form validation? I am sure that it is very simple, but I can not figure this one out to save my life. Thank you for you sharing your knowledge. I need to write WITHOUT jquery the following form validation. Whenever an error is encountered, prevent the form from being submitted. I need to use the window.onload function to assign a

问题 I have a matlab timer object. It is updating a global variable FOO once per second. I have a matlab GUIDE GUI, with a couple of controls, and a single plot frame. The plot frame gets updated by some of the GUI controls, and it gets updated by the timer object. Basically, there are two global variable FOO and BAR. The timer updates FOO, the GUI controls updates BAR. updates to either FOO or BAR need to update the GUI. How to do this? Thanks John 回答1: You can NOT put a watch on a variable.

问题 I start JVM from C++ program. C++ code: JNIEXPORT jobject JNICALL com_javelin_JavelinMarketData_callBackIntoNative(JNIEnv* env, jobject obj, jlong ptr) { std::cout << "com_javelin_JavelinMarketData_callBackIntoNative called" << std::endl; } int main() { JavaVM* jvm; JNIEnv* env; ... JNI_CreateJavaVM(&jvm, (void **)&env, &args); jmethodID mainMethod = env->GetStaticMethodID(helloWorldClass, "main", "([Ljava/lang/String;)V"); env->CallStaticVoidMethod(helloWorldClass, mainMethod, ...); } then I

问题 I have been searching Google and SO, but I am having a hard time wrapping my brain around this for some reason. Just to emphasize, I do NOT want to load a library like JQuery, since I don't need the majority of it. And while I could use an animation library, I've already built the few functions I need myself (some of them aren't even standard animations you would find in a library), so I'm not sure those would even be helpful. In fact, I could just as easily title this question "How to -

问题 I am using mongoose as ODM for a nodejs-mongodb application. Is my first nodejs application and I come from a non functional programming background. Looking at the docs of mongoose you can find: Kitten.find(function (err, kittens) { if (err) return console.error(err); console.log(kittens); }); So great, here we have the find function as part of our model (Kitten) and it actually can find the document and retrieve it inside the callback function as "kittens", and in this case it uses console

问题 I have two function that accept an array as parameter, these function do a simple work, making all element of the array to zero. First function using forEach() method and passing a callback to it: function pass_arr(x) { x.forEach(function(y){ y = 0; }); } And I call it this way: var a = ["a", "b", 1, 3, "stringg"]; pass_arr(a); Then printing the content of array a: for(var i = 0; i < a.length; i++) { console.log(a[i]); } I execute this using node: #nodejs func.js and got the result a b 1 3