No error , No gain

After an AJAX request, sometimes my application may return an empty object, like: var a = {}; How can I check whether that's the case? ECMA 5+: // because Object.keys(new Date()).length === 0; // we have to do some additional check obj // null and undefined check && Object.keys(obj).length === 0 && obj.constructor === Object Note, though, that this creates an unnecessary array (the return value ..

In SQL Server, it is possible to insert rows into a table with an INSERT.. SELECT statement: INSERT INTO Table (col1, col2, col3) SELECT col1, col2, col3 FROM other_table WHERE sql = 'cool' Is it also possible to update a table with SELECT? I have a temporary table containing the values and would like to update another table using those values. Perhaps something like this: UPDATE Table SET col1,..

I want to be able to do the following: Create a local branch based on some other (remote or local) branch (via git branch or git checkout -b) Push the local branch to the remote repository (publish), but make it trackable so git pull and git push will work immediately. How do I do that? I know about --set-upstream in Git 1.7, but that is a post-creation action. I want to find a way to make a sim..

How can you enumerate an enum in C#? E.g. the following code does not compile: public enum Suit { Spades, Hearts, Clubs, Diamonds } public void EnumerateAllSuitsDemoMethod() { foreach (Suit suit in Suit) { DoSomething(suit); } } And it gives the following compile-time error: 'Suit' is a 'type' but is used like a 'variable' It fails on the Suit keyword, the second one. foreach (Suit suit in (Suit..

I use object != null a lot to avoid NullPointerException. What is an alternative to: if (someobject != null) { someobject.doCalc(); } This to me sounds like a reasonably common problem that junior to intermediate developers tend to face at some point: they either don't know or don't trust the contracts they are participating in and defensively overcheck for nulls. Additionally, when writing thei..

This question's answers are a community effort. Edit existing answers to improve this post. It is not currently accepting new answers or interactions. I wrote the wrong thing in a commit message. How can I change the message? The commit has not been pushed yet. Amending the most recent commit message git commit --amend will open your editor, allowing you to change the commit message of the most ..

Is it possible to toggle the visibility of an element, using the functions .hide(), .show() or .toggle()? How would you test if an element is visible or hidden? Since the question refers to a single element, this code might be more suitable: // Checks CSS content for display:[none|block], ignores visibility:[true|false] $(element).is(":visible"); // The same works with hidden $(element).is(":hid..

Want to improve this post? Provide detailed answers to this question, including citations and an explanation of why your answer is correct. Answers without enough detail may be edited or deleted. I mistakenly added files to Git using the command: git add myfile.txt I have not yet run git commit. Is there a way to undo this, so these files won't be included in the commit? You can undo git add bef..

How do I discard changes in my working copy that are not in the index? For all unstaged files in current working directory use: git checkout -- . For a specific file use: git checkout -- path/to/file/to/revert -- here to remove ambiguity (this is known as argument disambiguation). For Git 2.23 onwards, one may want to use the more specific git restore . resp. git restore path/to/file/to/revert t..

Programming language books explain that value types are created on the stack, and reference types are created on the heap, without explaining what these two things are. I haven't read a clear explanation of this. I understand what a stack is. But, Where and what are they (physically in a real computer's memory)? To what extent are they controlled by the OS or language run-time? What is their sco..