In JavaScript, the "this" keyword inside an arrow function is defined by its _________ context.
- Global
- Lexical
- Local
- Execution
In JavaScript, the "this" keyword inside an arrow function is defined by its lexical context. Unlike regular functions, arrow functions do not have their own "this" binding, so they inherit the "this" value from the surrounding code block, which is determined by the lexical scope.
How does the “for...of” loop differ from the traditional "for" loop?
- It cannot iterate over arrays.
- It can only be used for asynchronous operations.
- It is specifically designed for iterating over arrays and iterable objects.
- It has better performance when iterating over objects.
The "for...of" loop is used for iterating over arrays and iterable objects, providing a simplified syntax compared to the traditional "for" loop. It's particularly useful when dealing with collections of data, offering cleaner code for iteration. Traditional "for" loops are more versatile but require more verbose code for array iteration.
What is "explicit binding" in JavaScript with regard to the "this" keyword?
- Explicit binding refers to manually setting the "this" value for a function using methods like .bind(), .call(), or .apply().
- Explicit binding is when "this" is automatically determined by the JavaScript engine.
- Explicit binding involves using the "this" keyword without any special methods.
- Explicit binding is only applicable to arrow functions.
In JavaScript, "explicit binding" refers to the manual setting of the "this" value for a function. This is done using methods like .bind(), .call(), or .apply(), allowing you to explicitly specify the object that should be treated as "this" within the function. This is especially useful in cases where the default "this" behavior is not what you need.
What does the responseType property of an XMLHttpRequest object determine?
- The data type of the request
- The request method
- The URL of the request
- The timeout for the request
The responseType property of an XMLHttpRequest object determines the expected data type of the response. It allows you to specify whether you expect the response to be in text, JSON, XML, or other formats. Setting this property correctly is important for parsing and handling the response data properly in your JavaScript code.
A callback function is passed as an ________ to other functions and is executed after its parent function has completed.
- argument
- object
- attribute
- expression
A callback function is passed as an "argument" to other functions in JavaScript. It is a function that is executed after its parent function has completed its execution. This allows for asynchronous operations and event handling in JavaScript.
Which method returns a promise that resolves with the result of parsing the body text as JSON?
- .json() method
- .text() method
- .body() method
- .parseJSON() method
The .json() method of a Response object returned by fetch parses the response body text as JSON and returns a Promise that resolves with the parsed data. This method is commonly used when making API requests to obtain structured data in JSON format. The .text() method returns the response body as plain text, while .body() does not exist, and .parseJSON() is not a standard method in JavaScript.
The createElement method is used to create a new element in the _________.
- browser
- JavaScript
- document
- DOM
The createElement method in JavaScript is used to create a new HTML element within the Document Object Model (DOM). It allows you to dynamically create HTML elements that can be added to the web page or modified as needed.
How can one emulate the functionality of a switch statement using objects and functions in JavaScript?
- By creating an object where each property maps to a case label, and the corresponding values are functions to execute.
- By using a for loop to iterate through cases and execute corresponding functions.
- By using the "continue" keyword in a loop to simulate case behavior.
- By creating an array of functions, where each function corresponds to a case label.
To emulate the functionality of a switch statement in JavaScript, you can create an object where each property represents a case label, and the corresponding property values are functions that perform the desired actions. You can then use the input value to access the appropriate function from the object, effectively simulating switch behavior.
How do arrow functions handle arguments in comparison to traditional functions?
- Arrow functions don't have access to arguments.
- Arrow functions handle arguments the same way as traditional functions.
- Arrow functions receive arguments as a separate object.
- Arrow functions receive arguments as individual parameters.
Arrow functions do not have access to the arguments object like traditional functions do. Instead, they handle arguments the same way as regular functions if you explicitly define parameters. Each parameter corresponds to an argument passed to the function, allowing you to access them directly within the function body. The absence of the arguments object can be a limitation in certain scenarios.
Using the new keyword invokes a _______ that creates a new object.
- constructor
- function
- class
- prototype
Using the new keyword in JavaScript invokes a constructor function that creates a new object. This object is then initialized with properties and methods defined within the constructor function. The constructor function serves as a blueprint for creating objects.