Section 1
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What does bind do on an object function?
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Date created
Mar 1, 2020
Cards (60)
Section 1
(50 cards)
What does bind do on an object function?
Create a new instance of the function but change the context of the this statements in the function to the parameter passed. let newFunction = o.getID.bind(newCar);
Determine if a variable is not a number
Number.isNaN(myVar);
"abc" > "ZYX"
True Lower case has precedence over upper case
Method to call in constructor if inheriting properties from another class
super()
Destructuring Array let carIds = [1,2,5] Assign carId1, carId2, and carId3 to these elements
let [carId1,carId2,carId3] = carIds;
JavaScript will initialize variables to _________ let myNewVar;
undefined
Creating and exporting a class using a module
In a separate file export class myClass{...}
Include a css stylesheet in html
<link rel = 'stylesheet' type='text/css' href='mysheet.css'>
Create a new array of cars with only red cars. Use arrow function
let redCars = myCars.filter(car => car.color == 'red');
What does continue keyword do in loop?
Immediately ends current loop and iterates again. No more code is run for that current block
let o = { cardId: 123, getID: function(prefix,postfix){ console.log(prefix + this.cardId + postifx)}} let newCar = { carId: 456 } Use apply function to run the getID function with newCar context
o.getID.apply(newCar,['ID: ', ' for car'])
Does JavaScript support extends for classes?
Yes
Change text of div with id 'myId' to 'Hello World'
var myDiv = document.getElementById('myId') myDiv.innerText = 'Hello World'
let o = { cardId: 123, getID: function(){ console.log(this.cardId)}} let newCar = { carId: 456 } Use bind to create a new function with newCar as the context for this in getID
let newFunction = o.getID.bind(newCar);
let o = { cardId: 123, getID: function(){ console.log(this.cardId)}} let newCar = { carId: 456 } Use call function to run the getID function with newCar context
o.getID.call(newCar);
BOM
Browser object model
Common Built-in JavaScript objects
Math, Date, String, Number
let year = "1967"; console.log(-year);
-1967
IIFE
Immediately invoked function expressions Calling the function immediately after declaring it (function(){console.log('hi')})() Used for closures
Importing a class from a module
import { myClass } from './myFolder/myClass.js'
let year = 1967; console.log(++year);
1968
What are call and apply?
Changing to context of the this keyword to what is passed when calling a function on an object. Apply allows for parameters to be passed as well myObj.runFunction.call(newObject) myObj.runFunction.apply(newObject,[param1,param2])
Get if button is clicked with jquery
$('#myButton').click(function(){})
CSS Preprocessor
An extension of the CSS language that adds variables, functions, and many other techniques. Example: Less
Where does stylesheet go in html?
in <head>
Loop through all car objects in array, printing out car names and index of that car using arrow function
myCars.forEach((car,index) => console.log(car + index));
Create an arrow function with prefix and suffix parameters that prints PREFIX is great with SUFFIX
let myFunction = (prefix,suffix) => prefix + 'is great with' + suffix; OR let myFunction = (prefix,suffix) => {return prefix + 'is great with' + suffix;}
Type of undefined variable
Undefined
Can you change properties of an object when you pass that object to a function?
Yes
Get and remove first element of an array
array.shift();
Ensure that all car objects in myCars array is red. If not print false.
let allRed = myCars.every(car => car.color === 'red');
The window object
The global object in JavaScript. Console and alert is on this
Rest Parameters
Hold multiple values as passed to the function function displayCars(...allCarIds){...} displayCars(100,200,300,250)
Find the first red car object in an array of cars
let car = myCars.find(car => car.color === 'red');
Get if button is clicked without jquery
var element = document.getElementById('myButtonId'); element.addEventListener("click",function(){}); OR <button onclick="doSomething">
Type of null variable
object
Create a constructor function to create a car with an id property
function Car(carId){ this.carId = carId; } let myCar = new Car();
What is a framework for html?
When http request is made to a server, a framework is in the middle. It performs advanced operations and then returns HTML that was requested. Examples: PHP, JAVA, ASP.NET MVC, WordPress.com
Where to add scripts to the DOM
In body, above </body> tag
Get style of element without jquery
var element = document.getElementById('myId'); element.style.display = 'block'
Interpreted language (scripting language)
A language that is run one statement at a time by another program called an interpreter. It doesn't need to be compiled Python, Javascript, C#.
Create javascript class car with constructor that sets car id
class Car{ constructor(carId){this.carId = carId} } let myCar = new Car(12);
setTimeout
Calls a function or evaluates an expression after a specified number of milliseconds setTimeout(function(){ ... },1000}
let year = "1967"; console.log(typeof(+year));
Number
let trackCar = function(carId, city){...} Change default city parameter to New York
let trackCar = function(carId, city = "New York"){...}
setInterval
Calls a function or evaluates an expression at specified intervals (in milliseconds) setInterval(function(){ ... },1000}
let year = 1967; console.log(year++);
1967 year is now 1968
Add JavaScript file to DOM
<script src = 'myScript.js'>
Destructuring Objects let myObject = { id:1, name:'llama'} Assign id to variable myId and name to variable myName
let { myId, myName } = myObject
Remove second element from an array
array.splice(1,1)
Section 2
(10 cards)