Mastering JavaScript Basics

What method would you use to create a new array with elements that pass a test?

• Use the 'map' method.

• Use the 'filter' method.

• Use the 'forEach' method.

• Use the 'reduce' method.

How do you combine all elements of an array into a single value?

• Use array.concat() to merge arrays.

• Use array.reduce() in JavaScript or a similar folding function in other languages.

• Utilize array.filter() to select specific items.

• Apply array.map() to transform elements.

What is the purpose of the rest parameter in a function?

• The rest parameter is used to define default values for function parameters.

• The purpose of the rest parameter is to collect all remaining arguments into an array.

• The rest parameter limits the number of arguments a function can accept.

• The rest parameter is a way to create named parameters in a function.

How does the spread operator work in JavaScript?

• The spread operator combines multiple objects into one.

• The spread operator is used to create a new array from an existing one.

• The spread operator in JavaScript expands elements of an iterable into individual elements.

• The spread operator is a method for defining functions in JavaScript.

What is variable scope and why is it important?

• Variable scope is the method of defining variable types in a programming language.

• Variable scope refers to the physical location of a variable in memory.

• Variable scope is the context in which a variable is accessible in a program, and it is important for managing variable visibility, memory usage, and preventing conflicts.

• Variable scope is the process of encrypting variable data for security.

How do you declare a 2D array in JavaScript?

• let array2D = [1, 2, 3, 4];

• let array2D = {1: [2, 3], 4: [5, 6]};

• let array2D = new Array(2, 2);

• let array2D = [[1, 2], [3, 4]];

Which method would you use to find the length of a string?

• Use the 'length' property or function.

• Use the 'size' method.

• Count the number of characters manually.

• Apply the 'getLength()' function.

What is the syntax for a switch statement?

• switch(expression) { case value1: // code block; default: // code block; }

• switch(expression) { case value1: // code block; break; case value2: // code block; break; default: // code block; }

• switch(value1) { case expression: // code block; }

• switch { case value1: // code block; break; }

What does the checked property do in a checkbox input?

• The checked property determines the label text of the checkbox.

• The checked property changes the color of the checkbox.

• The checked property sets the size of the checkbox.

• The checked property determines if a checkbox is selected or not.

How do you write an if statement to check if a number is positive?

• if (number > 0) { /* code to execute if number is positive */ }

• if (number == 0) { /* code to execute if number is zero */ }

• if (number >= 0) { /* code to execute if number is non-negative */ }

• if (number < 0) { /* code to execute if number is negative */ }