Salesforce JavaScript Developer Study Guide: Asynchronous JavaScript and DOM Manipulation, Exams of Advanced Education

Download Salesforce JavaScript Developer Study Guide: Asynchronous JavaScript and DOM Manipulation and more Exams Advanced Education in PDF only on Docsity! Salesforce Javascript Developer 1 study guide complete update A promise is - CORRECT ANSWER an object returned by asynchronous code async/await syntax is syntactic sugar for - CORRECT ANSWER promises the async keyword is added to the front of a - CORRECT ANSWER function that should contain asynchronous code the await keyword is added to the front of an asynchronous function call that returns - CORRECT ANSWER a promise the insertAfter() method can be used to add an element to the DOM after a given element (T/F) - CORRECT ANSWER False. There is an insertBefore() method but no insertAfter() method. A javascript object can be stored in a browser's localStorage using - CORRECT ANSWER JSON.stringify() What are the additional reload options available via long click in Chrome? - CORRECT ANSWER - Normal Reload - Hard Reload - Empty Cache and Hard Reload DevTools must be open to access these options. This method creates a table body - CORRECT ANSWER table.createTBody() This method inserts a table row - CORRECT ANSWER table.insertRow() What are two ways to listen for events in js? - CORRECT ANSWER - addEventListener() - an onevent handler (onclick, onmouseup, etc.) What are the two phases of event propagation in modern browsers? - CORRECT ANSWER - bubbling (goes from target to outermost ancestor) - capturing (goes from outermost ancestor to target) How is a custom event created and dispatched? - CORRECT ANSWER 1. CustomEvent() to create 2. dispatchEvent() to dispatch ex: const myEvent = new customEvent( What objects can addEventListener() target? - CORRECT ANSWER Any object that supports events, including Element, Document, and Window What parameters can be passed to addEventListener()? - CORRECT ANSWER - an options object - useCapture (true or false) What are some benefits to using addEventListener()? - CORRECT ANSWER - can use multiple handlers for one event - allows controlling phase (bubbling/capturing) when activated What browser API can be used to get the device location? - CORRECT ANSWER Geolocation What browser API can be used to send notifications to the user? - CORRECT ANSWER Notifications What browser API can be used to store data client-side? - CORRECT ANSWER Web Storage What parameters does fetch() take? - CORRECT ANSWER - the path to the resource (required) - init, an object which can contain options such as: - method - headers - body - mode - credentials The fetch() method returns a ______ it can be called using these keywords: _____ - CORRECT ANSWER - promise - async / await The Geolocation API can be accessed through a call to - CORRECT ANSWER navigator.geolocation Location information can be accessed using - CORRECT ANSWER - Geolocation.getCurrentPosition() (current location) - Geolocation.watchPosition() (execute a function when the location changes) What parameters do Geolocation.getCurrentPosition() and Geolocation.watchPosition() accept? - CORRECT ANSWER - a success callback (required) - an error callback (optional) - a PositionOptions object (optional) What methods can be used to move through the user's history? - CORRECT ANSWER - back() - forward() - go() Where does history.pushState() add a page to the browser history? - CORRECT ANSWER at the top of the stack history.replaceState() replaces - CORRECT ANSWER the current history entry When the active history entry changes, this event is triggered - CORRECT ANSWER popstate What arguments do history.replaceState() and history.pushState() take? - CORRECT ANSWER - state (ex: {page: 3}) - title - url The popstate event is fired when - CORRECT ANSWER The active history entry changes while the user navigates the session history The URL API provides these two interfaces - CORRECT ANSWER - URL - URLSearchParams List web storage API methods to 1. retrieve 2. set 3. remove 4. clear all keys from storage - CORRECT ANSWER 1. Storage.getItem() 2. Storage.setItem() 3. Storage.removeItem() 4. Storage.clear() A cookie is set by - CORRECT ANSWER document.cookie = 'key=value;' Where can local storage, session storage and cookie data be viewed in the Chrome DevTools? - CORRECT ANSWER Application -> Storage Functions can't be nested in js (T/F) - CORRECT ANSWER False What is the difference in the value of the this keyword in traditional vs. arrow functions? - CORRECT ANSWER Traditional: the object that invoked the function, or else the global object Arrow: doesn't default to the global object. The value of this is determined by context A higher order function is - CORRECT ANSWER A function that takes a function as its inputs or creates a function as its output. What is hoisting? - CORRECT ANSWER Hoisting makes it so a function can be called before it is declared. This doesn't happen for function expressions. Closure allows code to - CORRECT ANSWER access its parent scope, even after that code has finished