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Test for existence of nested JavaScript object key
...don't want a TypeError because if one of the members is null or undefined, and you try to access a member, an exception will be thrown.
You can either simply catch the exception, or make a function to test the existence of multiple levels, something like this:
function checkNested(obj /*, level1, ...
Difference between JSON.stringify and JSON.parse
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JSON.stringify turns a JavaScript object into JSON text and stores that JSON text in a string, eg:
var my_object = { key_1: "some text", key_2: true, key_3: 5 };
var object_as_string = JSON.stringify(my_object);
// "{"key_1":"some text","key_2":true,"key_3":5}"
typeof(objec...
The object cannot be deleted because it was not found in the ObjectStateManager
...ext, outside of a TransactionScope. Moved the parent call inside the scope and same context and my problem was solved.
– dan richardson
Feb 7 '13 at 10:31
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UITableView row animation duration and completion callback
... closures you place the same code as in beginUpdates()/endUpdates section. And the completion is executed after all animations.
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Node.js version on the command line? (not the REPL)
I want to get the version of Node.js on the command line. I'm expecting to run a command like:
14 Answers
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Is there any performance gain in indexing a boolean field?
... think about it like a book. If there were only 3 kinds of words in a book and you index all of them, you would have the same number of index pages as normal pages.
There would be a performance gain if there are relatively few records of one value. For example, if you have 1000 records and 10 of t...
Eclipse executable launcher error: Unable to locate companion shared library
I had Eclipse Indigo installed on my computer with the Android plugin and it was working perfectly for about two weeks. Today, I updated java and quicktime then restarted my computer. When it booted back up, eclipse had completely vanished - all the program files have completely disappeared. When I ...
onMeasure custom view explanation
I tried to do custom component. I extended View class and do some drawing in onDraw overrided method. Why I need to override onMeasure ? If I didn't, everything seen to be right. May someone explain it? How should I write my onMeasure method? I've seen couple tutorials, but each one is a litt...
PHP: Convert any string to UTF-8 without knowing the original character set, or at least try
I have an application that deals with clients from all over the world, and, naturally, I want everything going into my databases to be UTF-8 encoded.
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How can I read inputs as numbers?
Why are x and y strings instead of ints in the below code?
10 Answers
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