JavaScript Execution Context Quiz

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Questions and Answers

When is the execution context's variable environment generated?

Before the function execution, during the function definition.
During the execution phase, when the function starts running.
Before the function execution, right during the function call. (correct)
During the function definition, but only when the function is executed first time.

Which of the following is NOT part of the "Variable Environment" within an execution context?

Declarations of variables using `let`, `const`, and `var`.
The `this` keyword's binding within the function. (correct)
The `arguments` object, containing the arguments passed to the function.
Function definitions defined within the function's scope.

How does the `this` keyword's binding work differently in regular functions compared to arrow functions?

In both types of functions, `this` is always bound to the global object.
Arrow functions do not have their own `this` binding. They inherit `this` from the surrounding context. (correct)
Arrow functions dynamically bind `this` based on the calling context, while regular functions always bind `this` lexically to the context where they were defined.
Regular functions always bind `this` to the object that called them, while arrow functions bind `this` to the global object.

If a click event triggers a function to execute, how many execution contexts are involved?

Two, one for the global context and one for the click handler function. (B) Signup and view all the answers

What's the primary role of the "Scope Chain" within an execution context?

It's used to resolve variable names (identifiers) when they are referenced. (D) Signup and view all the answers

What happens to the execution context after a function finishes executing?

It's deleted from memory, releasing all its resources. (A) Signup and view all the answers

What is the purpose of the `arguments` object in the variable environment of an execution context?

It provides a dynamic way to pass arguments to a function, without explicitly declaring parameters. (B) Signup and view all the answers

Imagine a scenario where a function defined within another function is called. During the nested function's execution, where does the `scope chain` start its search for a variable?

It starts with the nested function's own scope. (D) Signup and view all the answers

Which of the following statements accurately describes the role of the Call Stack in the execution of JavaScript code?

The Call Stack manages the flow of execution within the current context, handling function calls and returns, and ensuring proper order of execution. (A) Signup and view all the answers

Which of the following best describes the relationship between the Call Stack and the Heap in JavaScript?

The Call Stack stores references to objects stored in the Heap, while the Heap stores the actual data. (D) Signup and view all the answers

Which of the following accurately describes the execution context of JavaScript code related to `DOM` event listeners?

The execution context for event listener functions is created when the event occurs, and is destroyed after the event listener function finishes executing. (C) Signup and view all the answers

Considering the execution of asynchronous operations such as timers and event listeners, when is the function associated with these operations executed?

Asynchronous function execution is managed by the <code>Event Loop</code>, where they are placed into a queue and are executed only after the current execution context is finished and the Call Stack is empty. (D) Signup and view all the answers

Which of the following best describes the relationship between the `Callback Queue` and the `Event Loop` in JavaScript?

The <code>Callback Queue</code> is a data structure where asynchronous functions are stored in order of their registration, waiting for the <code>Event Loop</code> to place them on the Call Stack for execution. (A) Signup and view all the answers

Which of the following statements best describes the purpose of the Global Execution Context in JavaScript?

The Global Execution Context serves as the primary execution context for all JavaScript code, regardless of whether it's inside a function or not. (C) Signup and view all the answers

Which of the following best describes the process of creating an execution context for a function in JavaScript?

An execution context is created for a function when the function is first called, and persists as long as the execution of the function continues. (D) Signup and view all the answers

Which of the following statements most accurately describes the relationship between the `Call Stack` and the `Event Loop` regarding the management of asynchronous operations in JavaScript?

The <code>Call Stack</code> and the <code>Event Loop</code> work in conjunction to ensure a smooth flow of execution, where the <code>Event Loop</code> manages asynchronous operations, and the <code>Call Stack</code> manages synchronous function execution. (C) Signup and view all the answers

What error message results from accessing a variable declared with 'let' before initialization?

ReferenceError: Cannot access 'variableName' before initialization (B) Signup and view all the answers

In which scenario does the 'this' keyword point to the global object?

When the function is invoked as a standalone function (A) Signup and view all the answers

What is the reason behind JavaScript's hoisting behavior?

To facilitate the use of function declarations before they are defined (B) Signup and view all the answers

Which statement about 'let' and 'const' variables is true regarding the Temporal Dead Zone (TDZ)?

'let' and 'const' variables cannot be used before and during their initialization. (A) Signup and view all the answers

What does the 'this' keyword refer to when used inside an arrow function?

The parent context where the arrow function was defined (B) Signup and view all the answers

How does the use of 'var' impact variable declarations in regards to hoisting and TDZ?

'var' variables are hoisted and initialized to 'undefined', avoiding TDZ issues. (A) Signup and view all the answers

Which behavior associated with function expressions is affected by variable declaration types?

Only 'var' allows function expressions to be hoisted without error. (C) Signup and view all the answers

What best describes the execution context's role in relation to the 'this' keyword?

Execution context is created at function invocation and sets the 'this' value dynamically. (D) Signup and view all the answers

What is the primary role of garbage collection in the context of 'Garbage-collected' as a defining characteristic of Javascript?

Managing memory allocation and deallocation automatically, preventing memory leaks. (A) Signup and view all the answers

Which of the following best describes the concept of 'Multi-paradigm' as it relates to JavaScript?

It allows developers to choose from various programming paradigms like object-oriented, functional, and procedural, but it is not strictly necessary for all applications. (C) Signup and view all the answers

What is the defining characteristic of 'First-class functions' as a feature of JavaScript?

Functions can be passed as arguments to other functions, returned from functions, and assigned to variables, allowing for functional programming techniques. (B) Signup and view all the answers

What is the main purpose of the 'Non-blocking event loop' in JavaScript?

To keep the browser responsive while handling long-running tasks, such as network requests, without blocking user interactions. (A) Signup and view all the answers

How does 'Dynamic' as a property of JavaScript impact its behavior?

It allows developers to create and manipulate data structures on the fly, adapting to changing requirements without rigid constraints. (A) Signup and view all the answers

What is the relationship between JavaScript and its execution environment?

JavaScript is heavily dependent on a specific execution environment, like the web browser, which provides the runtime environment for script execution. (A) Signup and view all the answers

Which of the following best describes the process of 'Interpreted or just-in-time compiled' in the context of JavaScript, as highlighted in the content?

JavaScript code is first converted into an intermediate representation (bytecode) and then executed by the browser's JavaScript engine. (A) Signup and view all the answers

How does JavaScript achieve 'Single-threaded' execution in the context of its event loop, as described in the content?

JavaScript processes tasks sequentially, with only one task running at a time, leveraging the event loop to handle asynchronous operations. (B) Signup and view all the answers

Which of the following statements about the call stack is false?

The call stack is responsible for managing the values of variables declared inside functions before execution. (A) Signup and view all the answers

In the context of JavaScript, what is the primary purpose of 'lexical scoping'?

Establishing the accessibility of variables based on their position in the code. (A) Signup and view all the answers

Consider the following code snippet:

function outer() {
  let outerVar = 'Hello';
  function inner() {
    console.log(outerVar);
  }
  inner();
}
outer();

What is the scope of the variable outerVar?

Function scope, only accessible within the <code>outer</code> function. (B) Signup and view all the answers

What is the role of the 'execution context' in JavaScript?

It creates and stores information related to the execution of a function. (B) Signup and view all the answers

Which of the following statements about the 'scope chain' is true?

It is a path used to search for variable references, starting from the current scope and moving outwards. (D) Signup and view all the answers

Which of the following statements about function scope in JavaScript is incorrect?

Function scope allows variables declared within the function to be accessed from the outside. (D) Signup and view all the answers

When does 'this' keyword resolve to the global object in JavaScript?

In non-strict mode and when called as a regular function. (B) Signup and view all the answers

Which of the following is NOT a characteristic of JavaScript's variable environment?

It determines the order in which functions are executed. (A) Signup and view all the answers

If the `first()` function was called before the `second()` function and then the `third()` function was called, which variable from the global scope would be available in the `third()` function's scope?

<code>a</code> (B) Signup and view all the answers

Which of the following statements about the Call Stack is TRUE?

The Call Stack is a data structure where function executions are stored. (D) Signup and view all the answers

Flashcards

High-level language

A programming language that abstracts details of the computer’s hardware.

Garbage collection

Automatic memory management that frees up unused memory.