JS-Dev-101 試験問題を無料オンラインアクセス

Refer to the code snippet:
01 let array = [1, 2, 3, 4, 4, 5, 4, 4];
02 for (let i = 0; i < array.length; i++) {
03 if (array[i] === 4) {
04 array.splice(i, 1);
05 i--;
06 }
07 }
What is the value of array after the code executes?

• A.[1, 2, 3, 4, 5, 4, 4]
• B.[1, 2, 3, 4, 4, 5, 4]
• C.[1, 2, 3, 5]
• D.[1, 2, 3, 4, 5, 4]

A team at Universal Containers works on a big project and uses Yarn to deal with the project's dependencies. A developer added a dependency to manipulate dates and pushed the updates to the remote repository. The rest of the team complains that the dependency does not get downloaded when they execute yarn.
What could be the reason for this?

• A.The developer added the dependency as a dev dependency, and NODE_ENV is set to production.
• B.The developer missed the option --add when adding the dependency.
• C.The developer missed the option --save when adding the dependency.
• D.The developer added the dependency as a dev dependency, and YARN_ENV is set to production.

A developer copied a JavaScript object:
01 function Person() {
02 this.firstName = "John";
03 this.lastName = "Doe";
04 this.name = () => `${this.firstName},${this.lastName}`;
05 }
06
07 const john = new Person();
08 const dan = Object.assign({}, john);
09 dan.firstName = 'Dan';
How does the developer access dan's firstName, lastName?

• A.dan.name
• B.dan.firstName + dan.lastName
• C.dan.firstName() + dan.lastName()
• D.dan.name()

let sampleText = "The quick brown fox jumps";
Which three expressions return true for a substring?

• A.sampleText.indexOf('Quick') !== -1;
• B.sampleText.include('fox') !== -1;
• C.sampleText.indexOf('fox') !== -1;
• D.sampleText.includes('fox');
• E.sampleText.indexOf('quick') > -1;

Original code:
01 let requestPromise = client.getRequest;
03 requestPromise().then((response) => {
04 handleResponse(response);
05 });
The developer wants to gracefully handle errors from a Promise-based GET request.
Which code modification is correct?

• A.Add .catch to the Promise chain
• B.Use finally handler for errors
• C.(duplicate of A)
• D.try/catch around requestPromise().then(...)