Salesforce JavaScript-Developer-I 問題集

質問 1：
Refer to the code below:
const event = new CustomEvent(
//Missing Code
);
obj.dispatchEvent(event);
A developer needs to dispatch a custom event called update to send information about recordId.
Which two options could a developer insert at the placeholder in line 02 to achieve this?
Choose 2 answers
A. { type : 'update', recordId : '123abc' }
B. 'Update' , (recordId : '123abc'(
C. 'Update' , {Details : {recordId : '123abc'}}
D. 'Update' , '123abc'
正解：B,C

質問 2：
A developer is leading the creation of a new web server for their team that will fulfill API requests from an existing client.
The team wants a web server that runs on Node.Js, and they want to use the new web framework Minimalist.Js. The lead developer wants to advocate for a more seasoned back-end framework that already has a community around it.
Which two frameworks could the lead developer advocate for?
Choose 2 answers
A. Express
B. Angular
C. Koa
D. Gatsby
正解：B,D

質問 3：
A developer is creating a simple webpage with a button. When a userclicks this button for the first time, a message is displayed.
The developer wrote the JavaScript code below, but something is missing. The message gets displayed every time a user clicks the button, instead of just the first time.
01 functionlisten(event) {
02 alert ( 'Hey! I am John Doe') ;
03 button.addEventListener ('click', listen);
Which two code lines make this code work as required?
Choose 2 answers
A. On line 04, useevent.stopPropagation ( ),
B. On line 04, use button.removeEventListener(' click" , listen);
C. On line 02, use event.first to test if it is the first execution.
D. On line 06, add an option called once to button.addEventListener().
正解：B,D

質問 4：
Referto the following code:

Which two statement could be inserted at line 17 to enable the function call on line 18?
Choose 2 answers
A. leo.roar = () => { console.log('They\'re pretty good!'); );
B. Object.assign (leo. Tiger);
C. leo.prototype.roar = ( ) =>( console.log('They\'re pretty good!'); };
D. Object.assign (leo, tony);
正解：A,D

質問 5：
developer publishes a new version of a package with new features that do not break backward compatibility. The previous version number was 1.1.3.
Following semantic versioning format, what should the new package version number be?
A. 1.2.0
B. 1.1.4
C. 2.0.0
D. 1.2.3
正解：C

質問 6：
Which two console logs output NaN?
Choose 2 answers | |
A. console.loeg(10 / 'five');
B. console.log(parseInt ' ("two')) ;
C. console.log(10 / 0);
D. console.log(10 / Number('5) ) ;
正解：B,D

質問 7：
A developer has a web server running with Node.js. The command to start the web server is node server.js.
The web server started having
latency issues. Instead of a one second turnaround for web requests, the developer now sees a five second turnaround.
Which command can the web developer run to see what the module is doing during the latency period?
A. NODE_DEBUG=true node server.js
B. NODE_DEBUG=http,https node server.js
C. DEBUG=http, https node server.js
D. DEBUG=true node server.js
正解：D

質問 8：
Which statement accurately describes an aspect of promises?
A. .then() cannot be added after a catch.
B. In a.then() function, returning results is not necessary since callbacks will catch the result of a previous promise.
C. .then() manipulates and returns the original promise.
D. Arguments for the callback function passed to .then() are optional.
正解：D

質問 9：
Which code statement below correctly persists an objects inlocal Storage ?
A. const setLocalStorage= ( jsObject) => {window.localStorage.setItem(jsObject);}
B. const setLocalStorage = ( jsObject) => {window.localStorage.connectObject(jsObject));}
C. const setLocalStorage = (storageKey, jsObject) => {window.localStorage.persist(storageKey, jsObject);}
D. const setLocalStorage = (storageKey, jsObject) => {window.localStorage.setItem(storageKey, JSON.stringify(jsObject));}
正解：D