Functions
In JavaScript, a function is a block of code that can be reusable. Functions can accept input (called parameters) and return output (called return value).
To define a function in JavaScript, you use the function keyword, followed by the name of the function, a list of parameters (enclosed in parentheses), and the function body (enclosed in curly braces).
Here is an example of a function in JavaScript:
function greet(name) { console.log("Hello, " + name + "!");}
To call a function in JavaScript, you simply use its name followed by the list of arguments (enclosed in parentheses).
Here is an example of how to call the greet function:
greet("John"); // Output: "Hello, John!"
You can also define a function that returns a value using the return statement.
Here is an example of a function that returns a value:
function add(num1, num2) { return num1 + num2;}console.log(add(10, 5)); // Output: 15
Objects
In JavaScript, an object is a collection of key-value pairs. You can use objects to store data in a structured way.
To create an object in JavaScript, you use the {} curly braces and define the key-value pairs inside the braces.
Here is an example of an object in JavaScript:
var person = { name: "John", age: 30, occupation: "Developer"};
To access the values in an object, you use the . dot notation followed by the key.
Here is an example of how to access the values in the person object:
console.log(person.name); // Output: "John"console.log(person.age); // Output: 30console.log(person.occupation); // Output: "Developer"
You can also update the values in an object by simply reassigning them.
person.name = "Jane";person.age = 25;console.log(person.name); // Output: "Jane"console.log(person.age); // Output: 25
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Functions & Objects in JavaScript was originally published in JavaScript in Plain English on Medium, where people are continuing the conversation by highlighting and responding to this story.