What is the impact of ES6 Modules on asynchronous loading and module bundling tools compared to CommonJS?
- Increased bundle size due to module encapsulation
- Improved parallel loading of modules
- Slower loading of dependencies
- Limited compatibility with bundling tools
ES6 Modules support asynchronous loading and enable parallel loading of modules, improving performance. Additionally, they work seamlessly with modern module bundlers, leading to more efficient bundling and reduced bundle size.
If you are refactoring a set of classes representing different types of user accounts in a system, how would constructors and super assist in initializing properties common to all account types?
- Utilize constructors in each class without the super keyword.
- Rely on global variables to initialize common properties.
- Use the super keyword to invoke the parent class constructor for shared properties.
- Avoid constructors altogether and rely on setter methods.
Constructors and the super keyword are essential in refactoring user account classes. Constructors help initialize class-specific properties, while super facilitates the invocation of the parent class constructor, ensuring that common properties are appropriately initialized across all account types.
Default parameters can be combined with object destructuring to construct complex default values.
- Object Literals
- Object Destructuring
- Object Prototypes
- Object Methods
ES6 introduced object destructuring, allowing you to extract values from objects easily. When combined with default parameters, it becomes a powerful feature for defining functions with complex default values. The correct option, "Object Destructuring," signifies this technique.
In ES6, class properties are often initialized inside the ________ method.
- initialize
- constructor
- create
- new
Class properties in ES6 are commonly initialized inside the constructor method. This allows you to set initial values for properties when an object is created.
Can a for...of loop be used to iterate over a generator function's yielded values?
- Yes, a for...of loop can iterate over the yielded values of a generator function.
- No, for...of loops are not compatible with generator functions.
- Yes, but it requires additional syntax.
- No, generator functions can only be iterated using for...in loops.
Yes, a for...of loop can be used to iterate over a generator function's yielded values. The for...of loop automatically iterates over the values yielded by the generator, making it a convenient and readable way to consume generator values.
How can you handle potential undefined values when destructuring an object?
- Ignore the value
- Provide default values
- Throw an error
- Use try-catch block
When destructuring an object, you can provide default values to handle potential undefined values. If the property is not present in the object, the default value will be used. This helps prevent errors due to missing properties.
When higher-order functions are used for asynchronous programming, they often involve __________ to handle future results.
- Callbacks
- Closures
- Promises
- Observables
Promises are a type of higher-order function used for handling asynchronous operations in JavaScript. They provide a clean and structured way to work with asynchronous code by representing a value that might be available now, in the future, or never.
Static properties are useful for storing data that __________ across all instances of the class.
- varies
- fluctuates
- persists
- changes
Static properties in a class are shared among all instances, ensuring that the data remains consistent across different objects created from the same class. This is particularly useful for information that should be common to all instances.
Tree shaking can fail to eliminate unused code if modules are dynamically _______ at runtime.
- Imported
- Exported
- Loaded
- Unloaded
The correct option is (c) Loaded. Tree shaking may fail if modules are dynamically loaded at runtime. Dynamically loading modules introduces uncertainty about which modules will be used, making it challenging for the module bundler to perform effective tree shaking.
Which statement correctly initiates a dynamic import in ES6?
- import module from 'module'
- require('module')
- import('module')
- require.ensure(['module'], callback)
The correct syntax for initiating a dynamic import in ES6 is import('module'). This allows you to asynchronously load and work with modules at runtime, enhancing flexibility in the application structure.
Is it possible to call a static method from another static method within the same class?
- No, it leads to a syntax error.
- Yes, using the class name.
- No, static methods cannot call each other.
- Yes, using the this keyword.
Yes, it is possible to call a static method from another static method within the same class using the class name. Static methods are associated with the class and can be called using the class name to avoid confusion. Option B is correct.
In what scenarios is it not recommended to use arrow functions in JavaScript?
- In event handlers
- In methods of classes
- In functions with dynamic this
- In callback functions within a setTimeout
Arrow functions do not have their own 'this' context and inherit it from the enclosing scope. This can lead to unexpected behavior in functions that rely on the dynamic binding of 'this'. It is not recommended to use arrow functions in functions with dynamic 'this' requirements.