Test: Functions - 1 - Software Development MCQ

A function in JavaScript is a set of statements that performs a specific task.

Parameters allow us to pass values into a function for its operation.

The correct syntax to define a function in JavaScript is "function myFunction() {}".

A function expression is a way to define a function as a value of a variable.

Function declarations are hoisted, while function expressions are not.

The code defines a function named "greet" that logs "Hello, World!" to the console. Calling "greet()" executes the function, resulting in the output "Hello, World!".

The code defines a function named "sum" that takes two parameters and returns their sum. Calling "sum(3, 4)" passes the values 3 and 4 to the function, which returns the sum of 7. The result is then logged to the console.

The code defines a function expression named "multiply" that takes two parameters and returns their product. Calling "multiply(2, 5)" passes the values 2 and 5 to the function, which returns the product of 10. The result is then logged to the console.

The code declares a global variable "x" with the value 5. The function "updateX" declares a local variable "x" with the value 10 but does not modify the global variable. Calling "updateX()" has no effect on the value of the global "x". Therefore, the output is 5.

The code declares a global variable "x" with the value 5. The function "updateX" modifies the global variable "x" by assigning it the value 10. Calling "updateX()" updates the value of the global "x". Therefore, the output is 10.

The code defines a function expression named "calculate" that takes three parameters: "a", "b", and "operation". The "operation" parameter is expected to be a function. In this case, the "add" function is passed as an argument to "calculate". The "calculate" function then calls the "operation" function with the values of "a" and "b". So, "calculate(3, 4, add)" is equivalent to "add(3, 4)", which returns the sum of 7. The result is then logged to the console.

The code defines a function named "outer" that declares a variable "x" with the value 10. Inside "outer", there is a nested function named "inner" that logs the value of "x" to the console. Finally, the "inner" function is returned from "outer" and assigned to the variable "closureFn". Calling "closureFn()" executes the "inner" function, which accesses the value of "x" from its outer scope. Therefore, the output is 10.

The code defines a function named "multiplyBy" that takes a parameter "factor" and returns an inner function. The inner function takes a parameter "number" and multiplies it by the "factor" value captured in its closure. By calling "multiplyBy(2)", we create a closure that multiplies any number by 2. Similarly, calling "multiplyBy(5)" creates a closure that multiplies any number by 5. Therefore, "multiplyByTwo(3)" returns 6, and "multiplyByFive(4)" returns 20.

The code defines a function named "outer" that declares a variable "x" with the value 10. Inside "outer", there is a nested function named "inner" that logs the value of "x" to the console. However, before the console log, there is a variable declaration "var x = 20". This declaration creates a new local variable "x" within the "inner" function's scope. Since JavaScript has function-level scope, the declaration of the local "x" variable shadows the outer "x" variable. Therefore, when the console log is executed, the value of the local "x" variable, which is undefined, is logged.

The code declares a global variable "x" with the value 5. The function "updateX" modifies the global variable "x" by assigning it the value 10. However, the function "updateX" is called asynchronously using "setTimeout" with a delay of 1000 milliseconds. Therefore, the console log is executed before the "updateX" function has a chance to modify the value of "x". Hence, the output is 5.