What is the purpose of the "module" field in a package.json file in an ES6 project?
- Enables the use of ECMAScript modules
- Specifies the version of ECMAScript
- Declares the project as a Node.js module
- Defines the project as an ES6 project
The "module" field in package.json is used to indicate that the project is using ECMAScript modules. This allows the use of the import and export statements in the project. It is crucial for enabling the ES6 module system in Node.js and browsers.
Q1: In a project where you are required to create multiple types of user profiles, how would you use prototypes to ensure code reusability and efficiency?
- Utilize Object.create()
- Use Object.assign()
- Employ class inheritance
- Implement mixin patterns
Prototypes play a crucial role in JavaScript's object-oriented design. Utilizing mixin patterns allows you to compose functionalities from multiple objects, ensuring modular and reusable code. This approach helps in creating diverse user profiles by combining specific traits through prototypes.
What happens to the entries in a WeakMap when there are no other references to the key?
- They are automatically removed from the WeakMap
- They are retained in the WeakMap
- They trigger an error
- They are marked for deferred removal
In a WeakMap, entries are automatically removed when there are no other references to the key. This behavior makes WeakMap suitable for scenarios where memory management is crucial, and entries should be tied to the existence of their key elsewhere in the program.
Recursive functions can be used effectively for tasks such as __________ traversal in data structures.
- Depth-first
- Breadth-first
- Pre-order
- Post-order
Recursive functions are commonly employed for depth-first traversal, where the function explores as far as possible along each branch before backtracking.
In a large-scale application with multiple JavaScript modules, how would you apply tree shaking to reduce the size of the deployed bundle?
- Use a bundler like Webpack that supports tree shaking.
- Manually remove unused code from each module.
- Convert the modules to CommonJS format.
- Utilize a code minification tool.
Tree shaking involves removing dead code during the bundling process. Webpack, a popular bundler, has built-in support for tree shaking, making it an efficient choice. Manually removing code or changing the module format is not the standard approach for tree shaking. Code minification is related but doesn't specifically address dead code elimination.
Consider a scenario where you have an iterable data structure with complex logic for each iteration. How would using a for...of loop simplify or complicate the implementation?
- It would simplify the implementation.
- It would complicate the implementation.
- It would have no impact on the implementation.
- It depends on the specific logic involved.
The correct option is "It would simplify the implementation." The for...of loop is designed to iterate over iterable objects, and its syntax is concise and clear. When dealing with complex logic for each iteration, using for...of can enhance code readability and maintainability by focusing on the logic rather than the mechanics of iteration.
When using default export, you can rename the imported module without using the _________ syntax.
- import customName from
- import as customName from
- import {customName} from
- import default as customName
In ES6, when importing a module with a default export and renaming it, you use the import customName from 'moduleName'; syntax. The as keyword is not required in this context.
What method is used to resume the execution of a generator function?
- resume()
- continue()
- next()
- run()
The correct method to resume the execution of a generator function is next(). This method is called on the Generator object and proceeds to the next yield statement, returning the yielded value. Options a), b), and d) are incorrect and not used for resuming a generator function.
Tagged template literals allow you to parse template literals with a _________ function.
- Regular
- Parse
- Tag
- Transform
In ES6, tagged template literals use a tag function to parse the template literal. This function, often referred to as the tag, allows you to process the template and its interpolated values before producing the final string.
How does the 'use strict' mode affect class behavior in ES6?
- It enforces stricter type checking in class properties
- It allows for dynamic addition of properties in a class
- It has no impact on class behavior
- It throws an error if the class contains undeclared variables
In 'use strict' mode, the class behavior becomes more rigid. It disallows the usage of undeclared variables, ensures that the 'this' keyword behaves more predictably, and generally promotes safer coding practices.