JavaScript Basics: Variables, Functions, Loops, Arrays, Objects Quiz

JavaScript Basics: Variables, Functions, Loops, Arrays, Objects

Variables

Variables are named storage locations in JavaScript that hold values. They are declared with the let keyword, followed by the variable name. Here's an example:

let variableName;   // Declare a variable without initializing it
variableName = 5;    // Initialize a variable
console.log(variableName);  // Output: 5

Functions

Functions define blocks of reusable code. They consist of a name, optional parameters, and a body containing zero or more statements. Here's a simple example:

function functionName(parameter1, parameter2, ...) {
  // Body of the function goes here
}

To call a function, simply execute its name followed by any necessary arguments:

functionName(argument1, argument2, ...);

Loops

Loops repetitively perform an action while certain conditions remain true. Some types of loops include for, while, and do-while. Here's an example of a for loop:

for (initializer; condition; incrementor) {
  statement;
}

And here's a typical while loop:

while (condition) {
  statement;
}

Arrays

Arrays are ordered collections of values that can contain multiple items of the same or different types. They're created with square brackets:

const arrayName = [];  // Create an empty array
arrayName[index] = item;  // Set an item in the array
console.log(arrayName);  // Output: [...items]

Objects

Objects are powerful data structures, capable of holding properties and methods. They're constructed with curly braces or literal notation:

const objectName = {};  // Create an empty object
objectName.property = value;  // Add a property to the object
objectName.method = () => { };  // Add a method to the object
console.log(objectName);  // Output: {...properties}

These fundamental aspects of JavaScript enable dynamic scripting, allowing developers to create complex programs that adapt to changing environments and user interactions.