Tutorial by Examples: arrow

6 When using arrow functions this takes the value from the enclosing execution context's this (that is, this in arrow functions has lexical scope rather than the usual dynamic scope). In global code (code that doesn't belong to any function) it would be the global object. And it keeps that way, eve...

Casting an instance of a base class to a subclass as in : b = (B) a; is called narrowing (as you are trying to narrow the base class object to a more specific class object) and needs an explicit type-cast. Casting an instance of a subclass to a base class as in: A a = b; is called widening and does...

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Arrow is an elegant JSON parsing library in Swift. It allows to parse JSON and map it to custom model classes with help of an <-- operator: identifier <-- json["id"] name <-- json["name"] stats <-- json["stats"] Example: Swift model struct Profile {...

Firstly, one can use quiver, where one doesn't have to deal with unhandy normalized figure units by use of annotation drawArrow = @(x,y) quiver( x(1),y(1),x(2)-x(1),y(2)-y(1),0 ) x1 = [10 30]; y1 = [10 30]; drawArrow(x1,y1); hold on x2 = [25 15]; y2 = [15 25]; drawArrow(x2,y2) ...

// Usage: drawLineWithArrows(50,50,150,50,5,8,true,true); // x0,y0: the line's starting point // x1,y1: the line's ending point // width: the distance the arrowhead perpendicularly extends away from the line // height: the distance the arrowhead extends backward from the endpoint // arrow...

// Usage: var p0={x:50,y:100}; var p1={x:100,y:0}; var p2={x:200,y:200}; var p3={x:300,y:100}; cubicCurveArrowHeads(p0, p1, p2, p3, 15, true, true); quadraticCurveArrowHeads(p0, p1, p2, 15, true, true); // or use defaults true for both ends with arrow heads cubicCurveArrowHeads(p0, p...

# creates a function with no arguments, which returns 3 get_three = () -> return 3 # same as above get_three = -> 3 # creates a function with arguments add_three = (num) -> num + 3 # multiple arguments, etc. add = (a, b) -> a + b

!!! Container should be positioned relatively or absolutely $direction - top, bottom, left, right $margin - margin by the edge in $direction. For top and bottom direction - it's from left to right. For left and right - it's from top to bottom. $colors - first is a border color, second - is a back...

Arrow functions automatically bind to the 'this' lexical scope of the surrounding code. performSomething(result => { this.someVariable = result }) vs performSomething(function(result) { this.someVariable = result }.bind(this))

Arrow functions will throw a TypeError when used with the new keyword. const foo = function () { return 'foo'; } const a = new foo(); const bar = () => { return 'bar'; } const b = new bar(); // -> Uncaught TypeError: bar is not a constructor...

Most of functions in D3.js accept an anonymous function as an argument. The common examples are .attr, .style, .text, .on and .data, but the list is way bigger than that. In such cases, the anonymous function is evaluated for each selected element, in order, being passed: The current datum (d) ...

new Vue({ el:"#star-wars-people", data:{ people: null }, mounted: function(){ $.getJSON("http://swapi.co/api/people/", data => this.people = data.results); } }) Caution! Arrow functions are a syntax introduced in Ecmascript 2015. It is not yet supp...

new Vue({ el:"#app", data:{ foo: "bar" }, methods:{ // This is wrong! Arrow functions capture "this" lexically // and "this" will refer to the window. doSomething: () => this.foo = "baz" } })

val lastNames = people.map(p => p.lastName) // Or shorter: val lastNames = people.map(_.lastName)

Let's consider this example, that outputs the squares of the numbers 3, 5, and 7: let nums = [3, 5, 7] let squares = nums.map(function (n) { return n * n }) console.log(squares) Run in RunKit The function passed to .map can also be written as arrow function by removing the function keywor...

import scalaz._ import Scalaz._ scala> val plus1 = (_: Int) + 1 plus1: Int => Int = $$Lambda$1167/1113119649@6a6bfd97 scala> val plus2 = (_: Int) + 2 plus2: Int => Int = $$Lambda$1168/924329548@6bbe050f scala> val rev = (_: String).reverse rev: String => String = $$Lambd...

Arrow function is the new way of defining a function in ECMAScript 6. // traditional way of declaring and defining function var sum = function(a,b) { return a+b; } // Arrow Function let sum = (a, b)=> a+b; //Function defination using multiple lines let checkIfEven = (a) => { ...

this in function refers to instance object used to call that function but this in arrow function is equal to this of function in which arrow function is defined. Let's understand using diagram Understanding using examples. var normalFn = function(){ console.log(this) // refers to global/windo...

Using arrow function as callback function can reduce lines of code. The default syntax for arrow function is () => {} This can be used as callbacks For example if we want to print all elements in an array [1,2,3,4,5] without arrow function, the code will look like this [1,2,3,4,5].forEach...