Sangrene

function Square(props) { // The properties of the square contain the "onClick" function as well as the "value" number
    return (
      <button className="square"
              onClick={props.onClick}>{/** (1)  When I click on the button, it triggers the function onClick from the props object. */}

          {props.value}
      </button>
    );
}

gaearon

If you haven’t worked with JavaScript in the last few years, these three points should give you enough knowledge to feel comfortable reading the React documentation:

• We define variables with let and const statements. For the purposes of the React documentation, you can consider them equivalent to var.
• We use the class keyword to define JavaScript classes. There are two things worth remembering about them. Firstly, unlike with objects, you don't need to put commas between class method definitions. Secondly, unlike many other languages with classes, in JavaScript the value of this in a method [depends on how it is called](https://developer.mozilla.org/en-US/docs/Web/Jav

yangcha

LIST OF MAT TYPE IN OPENCV

from http://ninghang.blogspot.com.es/2012/11/list-of-mat-type-in-opencv.html

credit to: https://www.blogger.com/profile/03087225378863523119

A Mapping of Type to Numbers in OpenCV

	C1	C2	C3	C4
CV_8U	0	8	16	24
CV_8S	1	9	17	25

jamesmartin

import IOBluetooth
// See https://developer.apple.com/reference/iobluetooth/iobluetoothdevice
// for API details.

class BluetoothDevices {
  func pairedDevices() {
    print("Bluetooth devices:")
    guard let devices = IOBluetoothDevice.pairedDevices() else {
      print("No devices")
      return

ozh

#How to create a .file or .folder on Windows

There are several ways

1. Rename

• Create file.txt
• Rename to .file., the last dot will be dropped, you'll have .file

Works the same with a file or a directory.