Tutorial by Examples: r

You can use a custom toJSON method and reviver function to transmit instances of your own class in JSON. If an object has a toJSON method, its result will be serialized instead of the object itself. 6 function Car(color, speed) { this.color = color; this.speed = speed; } Car.prototype.to...

JavaScript has two primary ways to represent binary data in the browser. ArrayBuffers/TypedArrays contain mutable (though still fixed-length) binary data which you can directly manipulate. Blobs contain immutable binary data which can only be accessed through the asynchronous File interface. Conver...

DataViews provide methods to read and write individual values from an ArrayBuffer, instead of viewing the entire thing as an array of a single type. Here we set two bytes individually then interpret them together as a 16-bit unsigned integer, first big-endian then little-endian. var buffer = new Ar...

var data = 'iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACN' + 'byblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHx' + 'gljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg=='; var characters = atob(data); var array = new Uint8Array(characters.length); for (var i = 0; i < characters.length; i++) { array[i] ...

TypedArrays are a set of types providing different views into fixed-length mutable binary ArrayBuffers. For the most part, they act like Arrays that coerce all assigned values to a given numeric type. You can pass an ArrayBuffer instance to a TypedArray constructor to create a new view of its data. ...

5.1 When you take a reference to a method (a property which is a function) in JavaScript, it usually doesn't remember the object it was originally attached to. If the method needs to refer to that object as this it won't be able to, and calling it will probably cause a crash. You can use the .bind...

Template literals are a special type of string literal that can be used instead of the standard '...' or "...". They are declared by quoting the string with backticks instead of the standard single or double quotes: `...`. Template literals can contain line breaks and arbitrary expression...

The String.raw tag function can be used with template literals to access a version of their contents without interpreting any backslash escape sequences. String.raw`\n` will contain a backslash and the lowercase letter n, while `\n` or '\n' would contain a single newline character instead. const p...

A function identified immediately before a template literal is used to interpret it, in what is called a tagged template literal. The tag function can return a string, but it can also return any other type of value. The first argument to the tag function, strings, is an Array of each constant piece...

Inheritance in Python is based on similar ideas used in other object oriented languages like Java, C++ etc. A new class can be derived from an existing class as follows. class BaseClass(object): pass class DerivedClass(BaseClass): pass The BaseClass is the already existing (parent)...

Instance variables are unique for each instance, while class variables are shared by all instances. class C: x = 2 # class variable def __init__(self, y): self.y = y # instance variable C.x # 2 C.y # AttributeError: type object 'C' has no attribute 'y' c1 = C(3) c1....

#! /bin/bash for i in 1 "test" 3; do #Each space separated statement is assigned to i echo $i done Other commands can generate statements to loop over. See "Using For Loop to Iterate Over Numbers" example. This outputs: 1 test 3

#! /bin/bash for i in {1..10}; do # {1..10} expands to "1 2 3 4 5 6 7 8 9 10" echo $i done This outputs the following: 1 2 3 4 5 6 7 8 8 10

In the same module Inside a module named "MyModule", Xcode generates a header named MyModule-Swift.h which exposes public Swift classes to Objective-C. Import this header in order to use the Swift classes: // MySwiftClass.swift in MyApp import Foundation // The class must be `public`...

If MyFramework contains Objective-C classes in its public headers (and the umbrella header), then import MyFramework is all that's necessary to use them from Swift. Bridging headers A bridging header makes additional Objective-C and C declarations visible to Swift code. When adding project files, ...

Supplying pow() with 3 arguments pow(a, b, c) evaluates the modular exponentiation ab mod c: pow(3, 4, 17) # 13 # equivalent unoptimized expression: 3 ** 4 % 17 # 13 # steps: 3 ** 4 # 81 81 % 17 # 13 For built-in types using modular exponentiation is only possible...

// use Write trait that contains write() function use std::io::Write; fn main() { std::io::stdout().write(b"Hello, world!\n").unwrap(); } The std::io::Write trait is designed for objects which accept byte streams. In this case, a handle to standard output is acquired with ...

Concatenate strings with the + operator to produce a new string: let name = "John" let surname = "Appleseed" let fullName = name + " " + surname // fullName is "John Appleseed" Append to a mutable string using the += compound assignment operator, or usi...

The -import-objc-header flag specifies a header for swiftc to import: // defs.h struct Color { int red, green, blue; }; #define MAX_VALUE 255 // demo.swift extension Color: CustomStringConvertible { // extension on a C struct public var description: String { return &q...

A module map can simply import mymodule by configuring it to read C header files and make them appear as Swift functions. Place a file named module.modulemap inside a directory named mymodule: Inside the module map file: // mymodule/module.modulemap module mymodule { header "defs.h&q...