A developer has an object `const config = { theme: 'dark', language: 'en' };` and needs to add a new property `fontSize` with the value `16`. Which code correctly adds the property?

`Object.freeze(config); config.fontSize = 16;`

`config.push({ fontSize: 16 });`

`config = { ...config, fontSize: 16 };`

A developer is refactoring a script that has a global variable `counter` used by multiple functions. The developer wants to prevent accidental reassignment of `counter` from other parts of the code, but still allow it to be incremented. Which approach is most appropriate?

Wrap the counter in an object and use `const` for the object reference.

Use `var counter = 0;` and rely on function scope to prevent external access.

Use `let counter = 0;` and freeze the variable with `Object.freeze(counter)`.

Use `const counter = 0;` and increment with `counter++`.

LPI Web Development Essentials

Domain 4Objective 2

034.2 JavaScript Data Structures (weight: 3) WEB-DEVELOPMENT-ESSENTIALS Practice Questions (Page 5)

Part of the 034 JavaScript Programming domain, which makes up ~16% of our current practice bank. Linux Professional Institute does not publish an official question count, but from its 60-minute exam (~25–40 total, ~4–6 in this domain), expect 1–2 from this objective — we provide 26 practice questions to prepare you well beyond it. (estimate)

26questions here

6free pages

10concepts

Questions 21–25

21application · easy
A developer has an object `const config = { theme: 'dark', language: 'en' };` and needs to add a new property `fontSize` with the value `16`. Which code correctly adds the property?
Select an answer first
22foundation · easy
Which keyword declares a variable that is function-scoped and can be redeclared in the same scope?
Select an answer first
23foundation · easy
What is the data type of the value null?
Select an answer first
24expert · medium
A developer is refactoring a script that has a global variable `counter` used by multiple functions. The developer wants to prevent accidental reassignment of `counter` from other parts of the code, but still allow it to be incremented. Which approach is most appropriate?
Select an answer first
25foundation · easy
Which function converts a value to a string explicitly?
Select an answer first

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034.2 JavaScript Data Structures (weight: 3) WEB-DEVELOPMENT-ESSENTIALS Practice Questions (Page 5)

Questions 21–25

A developer has an object `const config = { theme: 'dark', language: 'en' };` and needs to add a new property `fontSize` with the value `16`. Which code correctly adds the property?

Which keyword declares a variable that is function-scoped and can be redeclared in the same scope?

What is the data type of the value null?

A developer is refactoring a script that has a global variable `counter` used by multiple functions. The developer wants to prevent accidental reassignment of `counter` from other parts of the code, but still allow it to be incremented. Which approach is most appropriate?

Which function converts a value to a string explicitly?

Keep studying — 034 JavaScript Programming