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Detecting an undefined object property
...is the special value `undefined`");
}
To check if an object does not actually have such a property, and will therefore return undefined by default when you try and access it:
if(!o.hasOwnProperty('myProperty')) {
alert("myProperty does not exist");
}
To check if the value associated with an i...
How do I update my bare repo?
...
If you want to duplicate all the objects from the main repo, do this inside the main repo:
git push --all <url-of-bare-repo>
Alternatively, do a fetch inside the bare repo:
git fetch <url-of-main-repo>
You cannot do a pull, because ...
How can I add an item to a IEnumerable collection?
...s can be added. In fact, it does not necessarily represent a collection at all! For example:
IEnumerable<string> ReadLines()
{
string s;
do
{
s = Console.ReadLine();
yield return s;
} while (!string.IsNullOrEmpty(s));
}
IEnumerable<string> lines ...
Create instance of generic type in Java?
...type information is available via reflection. e.g.,
public abstract class Foo<E> {
public E instance;
public Foo() throws Exception {
instance = ((Class)((ParameterizedType)this.getClass().
getGenericSuperclass()).getActualTypeArguments()[0]).newInstance();
...
}
}
...
How to create enum like type in TypeScript?
...elease) you can use the enum definition like this:
enum TShirtSize {
Small,
Medium,
Large
}
var mySize = TShirtSize.Large;
By default, these enumerations will be assigned 0, 1 and 2 respectively. If you want to explicitly set these numbers, you can do so as part of the enum declaration....
How to profile methods in Scala?
What is a standard way of profiling Scala method calls?
12 Answers
12
...
Performance difference between IIf() and If
..."Hello")
' Usage 2
Dim foo = If(result, "Alternative")
The first is basically C#'s ternary conditional operator and the second is its coalesce operator (return result unless it’s Nothing, in which case return "Alternative"). If has thus replaced IIf and the latter is obsolete.
Like in C#, VB's ...
Check if a variable is a string in JavaScript
...ing both typeof and instanceof feels like good advice if your code may be called by others'. @MarkAmery's postmessage edge case matters if you're asking "what was I just postmessaged?" - but you'd expect that to be handled at the interface and not allowed to propagate. Elsewhere, it seems correct t...
#pragma once vs include guards? [duplicate]
... time but #pragma once is very well supported across compilers but not actually part of the standard. The preprocessor may be a little faster with it as it is more simple to understand your exact intent.
#pragma once is less prone to making mistakes and it is less code to type.
To speed up compil...
How to use base class's constructors and assignment operator in C++?
...
You can explicitly call constructors and assignment operators:
class Base {
//...
public:
Base(const Base&) { /*...*/ }
Base& operator=(const Base&) { /*...*/ }
};
class Derived : public Base
{
int additional_;
public:
...