Salesforce CRT-600 Exam Questions : Salesforce Certified JavaScript Developer I

A developer implements and calls the following code when an application state change occurs:
Const onStateChange =innerPageState) => {
window.history.pushState(newPageState, ' ', null);
}
If the back button is clicked after this method is executed, what can a developer expect?

• A. A popstate event is fired with a state property that details the application's last state.
• B. The page reloads and all Javascript is reinitialized.
• C. A navigate event is fired with a state property that details the previous application state.
• D. The page is navigated away from and the previous page in the browser's history is loaded.

Refer to the code below:
Let foodMenu1 = ['pizza', 'burger', 'French fries'];
Let finalMenu = foodMenu1;
finalMenu.push('Garlic bread');
What is the value of foodMenu1 after the code executes?

• A. [ 'Garlic bread']
• B. [ 'pizza','Burger', 'French fires', 'Garlic bread']
• C. [ 'Garlic bread' , 'pizza','Burger', 'French fires' ]
• D. [ 'pizza','Burger', 'French fires']

A developer wants to create an object from a function in the browser using the code below.

What happens due to the lack of the mm keyword on line 02?

• A. The m variable is assigned the correct object.
• B. window.name is assigned to 'hello' and the variable = remains undefined.
• C. The m variable is assigned the correct object but this.name remains undefined.
• D. window.m Is assigned the correct object.

is below:
<input type="file" onchange="previewFile()">
<img src="" height="200" alt="Image Preview..."/>
The JavaScript portion is:
01 function previewFile(){
02 const preview = document.querySelector('img');
03 const file = document.querySelector('input[type=file]').files[0];
04 //line 4 code
05 reader.addEventListener("load", () => {
06 preview.src = reader.result;
07 },false);
08 //line 8 code
09 }
In lines 04 and 08, which code allows the user to select an image from their local computer , and to display the image in the browser?

• A. 04 const reader = new File();
  08 if (file) URL.createObjectURL(file);
• B. 04 const reader = new FileReader();
  08 if (file) URL.createObjectURL(file);
• C. 04 const reader = new FileReader();
  08 if (file) reader.readAsDataURL(file);
• D. 04 const reader = new File();
  08 if (file) reader.readAsDataURL(file);

Which code statement below correctly persists an objects in local Storage ?

• A. const setLocalStorage = (storageKey, jsObject) => {
  window.localStorage.setItem(storageKey, JSON.stringify(jsObject));
  }
• B. const setLocalStorage = (storageKey, jsObject) => {
  window.localStorage.persist(storageKey, jsObject);
  }
• C. const setLocalStorage = ( jsObject) => {
  window.localStorage.setItem(jsObject);
  }
• D. const setLocalStorage = ( jsObject) => {
  window.localStorage.connectObject(jsObject));
  }