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What is the primary advantage of using composition over inheritance in ES6?

  • Code Reusability
  • Tight Coupling
  • Polymorphism
  • Encapsulation
In ES6, composition refers to combining simpler functions or objects to create more complex ones. The primary advantage is improved code reusability and flexibility, as it avoids the issues associated with tight coupling in inheritance. Composition promotes a more modular and maintainable code structure, allowing for better adaptability to changes.
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The __________ keyword is used for creating getter methods in an ES6 class.

  • Set
  • Get
  • Define
  • Getter
In ES6 classes, the get keyword is used to create getter methods. Getter methods allow you to retrieve the value of an object's property. When a getter method is defined using the get keyword, it is called without the need for parentheses, providing a more natural and property-like syntax when accessing the property.
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The method Symbol.for(__________) is used to create Symbols that are __________ across different scopes.

  • globalKey'
  • sharedKey'
  • scopedKey'
  • localKey'
Symbol.for() is used to create symbols that are shared across different scopes. It searches for an existing symbol with the given key and returns it if found; otherwise, it creates a new one. Example: const sharedSymbol = Symbol.for('sharedKey');
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In an event handler inside a React class component, what implications does using an arrow function have compared to a traditional function?

  • No difference
  • Better performance
  • Avoid using arrow functions
  • Avoid using traditional functions
Using an arrow function in a React class component's event handler can lead to better performance, as it avoids the need to bind "this" explicitly. However, it's essential to be cautious about potential memory leaks in certain scenarios.
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How does the extends keyword function in class inheritance in ES6?

  • It creates a copy of the parent class
  • It allows a class to inherit from multiple classes
  • It creates a subclass that inherits from a specified class
  • It is used to declare a private class member
In ES6, the extends keyword is used to create a subclass that inherits from a specified class. The subclass can then access the properties and methods of the parent class. This facilitates the concept of class inheritance in JavaScript.
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Dynamic imports in ES6 return a _________ which resolves to the module's exports.

  • Promise
  • callback function
  • string
  • module object
Dynamic imports in ES6 return a Promise, which resolves to the module's exports. This asynchronous loading mechanism helps in optimizing performance.
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When a function execution completes, it is removed from the __________.

  • Call Stack
  • Callback Queue
  • Event Loop
  • Heap
In JavaScript, the Call Stack is responsible for managing function execution. When a function completes its execution, it is popped off the Call Stack.
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How does ES6 module resolution differ between web browsers and Node.js environments?

  • Browsers use CommonJS, Node.js uses ECMAScript Modules
  • Browsers use ECMAScript Modules, Node.js uses CommonJS
  • Both use CommonJS
  • Both use ECMAScript Modules
Web browsers primarily support ECMAScript Modules, while Node.js traditionally used CommonJS. Understanding this distinction is important for developers working on projects that target both environments.
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In a web application with heavy DOM manipulations and API calls, how would the event loop and call stack manage these operations?

  • The event loop ensures that asynchronous operations, like API calls, are offloaded to the browser's APIs and queued in the task queue. The call stack, which handles synchronous operations, prioritizes execution of tasks in the stack.
  • The call stack manages synchronous operations, and the event loop coordinates the execution of asynchronous operations, ensuring they don't block the main thread.
  • The call stack processes synchronous tasks, and the event loop continuously checks the call stack and task queue, prioritizing tasks based on their readiness for execution.
  • The event loop delegates asynchronous tasks to the browser's APIs, which are executed separately from the main threaThe call stack manages synchronous tasks, preventing them from blocking the execution flow.
In a web application, the event loop and call stack work in tandem. The event loop coordinates asynchronous operations, preventing them from blocking the main thread. The call stack manages synchronous tasks, and the event loop offloads asynchronous tasks to the browser's APIs. Understanding this interaction is crucial for optimizing performance in applications with heavy DOM manipulations and API calls.
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In a scenario where you need to create a custom data structure (like a tree), how would you make it iterable?

  • Implement the iterable protocol by defining a Symbol.iterator method
  • Use the Array.from() method to convert the data structure to an array
  • Utilize the for...in loop to iterate over the data structure
  • Create a custom iterate method for the data structure
Making a custom data structure iterable involves implementing the iterable protocol by defining a Symbol.iterator method. This method should return an iterator object with a next method, allowing the data structure to be iterated using the for...of loop or other iterable mechanisms in JavaScript.
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