Often when programming it is necessary to make some distinction between a variable that has a value and one that does not. For reference types, such as C Pointers, a special value such as null can be used to indicate that the variable has no value. For intrinsic types, such as an integer, it is mo...
Sometimes, programmers who are new Java will use primitive types and wrappers interchangeably. This can lead to problems. Consider this example:
public class MyRecord {
public int a, b;
public Integer c, d;
}
...
MyRecord record = new MyRecord();
record.a = 1; // OK
...
You can use ReactJS's components easily in TypeScript. Just rename the 'jsx' file extension to 'tsx':
//helloMessage.tsx:
var HelloMessage = React.createClass({
render: function() {
return <div>Hello {this.props.name}</div>;
}
});
ReactDOM.render(<HelloMessage name=&q...
Optional Parameters
In TypeScript, every parameter is assumed to be required by the function. You can add a ? at the end of a parameter name to set it as optional.
For example, the lastName parameter of this function is optional:
function buildName(firstName: string, lastName?: string) {
// ...
Set the MONGO_URL environment variable before starting your local Meteor app.
Linux/MacOS Example:
MONGO_URL="mongodb://some-mongo-host.com:1234/mydatabase" meteor
or
export MONGO_URL="mongodb://some-mongo-host.com:1234/mydatabase"
meteor
Windows Example
Note: don't u...
The web.config system.web.httpRuntime must target 4.5 to ensure the thread will renter the request context before resuming your async method.
<httpRuntime targetFramework="4.5" />
Async and await have undefined behavior on ASP.NET prior to 4.5. Async / await will resume on an arb...
A commonly used CSS/Javascript library is Bootstrap. To install it into your Aurelia CLI driven application first you need to install it using Npm.
npm install bootstrap --save
Because Bootstrap has a hard dependency on jQuery, we need to make sure we also have jQuery installed:
npm install jqu...
SyncAdapter
/**
* Define a sync adapter for the app.
* <p/>
* <p>This class is instantiated in {@link SyncService}, which also binds SyncAdapter to the system.
* SyncAdapter should only be initialized in SyncService, never anywhere else.
* <p/>
* <p>The system ca...
Sometimes it is appropriate to use an immutable empty collection. The Collections class provides methods to get such collections in an efficient way:
List<String> anEmptyList = Collections.emptyList();
Map<Integer, Date> anEmptyMap = Collections.emptyMap();
Set<Number> anEmptySe...
Occasionally you'd want to catch an exception and throw it from a different thread or method while preserving the original exception stack. This can be done with ExceptionDispatchInfo:
using System.Runtime.ExceptionServices;
void Main()
{
ExceptionDispatchInfo capturedException = null;
...
To use Leaflet, load its stylesheet and JavaScript file to your page:
<link rel="stylesheet" href="/css/leaflet.css" />
<script src="/js/leaflet.js"></script>
These resources can be downloaded from a variety of locations such as Leaflet's homepage...
// *** Find movies except given ids ***
NSPredicate *filterByNotInIds = [NSPredicate predicateWithFormat:@"NOT (self.id IN %@)",@[@"7CDF6D22-8D36-49C2-84FE-E31EECCECB79", @"7CDF6D22-8D36-49C2-84FE-E31EECCECB76"]];
NSLog(@"Filter movies except given Ids : %@"...
In Android there is a default options menu, which can take a number of options. If a larger number of options needs to be displayed, then it makes sense to group those options in order to maintain clarity. Options can be grouped by putting dividers (i.e. horizontal lines) between them. In order to a...
Prerequisites
sudo apt-get install build-essential
sudo apt-get install python
[optional]
sudo apt-get install git
Get source and build
cd ~
git clone https://github.com/nodejs/node.git
OR
For the latest LTS Node.js version 6.10.2
cd ~
wget https://nodejs.org/dist/v6.3.0/node-v6.10....
The ** operator works similarly to the * operator but it applies to keyword parameters.
def options(required_key:, optional_key: nil, **other_options)
other_options
end
options(required_key: 'Done!', foo: 'Foo!', bar: 'Bar!')
#> { :foo => "Foo!", :bar => "Bar!" ...
