Non-primitive Data Types in JavaScript

Study Notes

Non-primitive Data Types in JavaScript

Arrays

Definition: A data structure used to store multiple values in a single variable.
Creation: Can be created using array literals [] or the Array constructor.
Methods:
- push(): Adds an element to the end.
- pop(): Removes the last element.
- shift(): Removes the first element.
- unshift(): Adds an element to the beginning.
- splice(): Adds/removes elements from any position.
- slice(): Returns a part of an array based on indices.
Accessing Elements: Use zero-based indexing (e.g., array[0] for the first element).
Iteration: Can be iterated using loops (e.g., for, forEach).

Objects

Definition: A collection of keyed values, useful for representing structured data.
Creation: Can be created using object literals {} or the Object constructor.
Properties: Key-value pairs; access a property using dot obj.key or bracket obj['key'] notation.
Methods: Functions stored as object properties; can be called as obj.method().
Iteration: Properties can be iterated using for...in loop or Object.keys(), Object.values(), and Object.entries() methods.

Functions

Definition: A block of code designed to perform a particular task. Functions are first-class citizens in JavaScript.

Creation:

Function declaration:
```
function name(params) { ... }
```
Function expression:
```
const name = function(params) { ... };
```
Arrow function:
```
const name = (params) => { ... };
```

Parameters and Arguments: Functions can take parameters; arguments are the values passed during invocation.
Return Values: Functions can return values using the return statement; no return is equivalent to returning undefined.
Scope: JavaScript functions create their own scope; variables declared inside a function are not accessible from outside.
Higher-order Functions: Functions that take other functions as arguments or return them. Examples: map(), filter(), reduce().

Arrays

Arrays are a data structure used to store multiple values under a single variable.
Arrays can be created using array literals [] or the Array constructor.
Arrays have various methods like push() to add an element at the end, pop() to remove the last element, shift() to remove the first element, unshift() to add an element at the beginning, splice() to add or remove elements from a specific position, slice() to return a section of the array based on indices.
Elements in an array can be accessed using zero-based indexing (e.g., array[0] for the first element).
Arrays can be iterated using loops like for or forEach.

Objects

Objects are a collection of key-value pairs, useful for representing structured data.
Objects can be created using object literals {} or the Object constructor.
Properties refer to the key-value pairs in an object accessed using dot obj.key or bracket obj['key'] notation.
Methods are functions stored as properties of an object and can be called using obj.method().
Object properties can be iterated using for...in loop or methods like Object.keys(), Object.values(), and Object.entries().

Functions

Functions in JavaScript are a block of code designed to perform a specific task.
Functions are first-class citizens, meaning they can be assigned to variables, passed as arguments to other functions, and returned from functions.
There are three main ways to create functions:
- Function declaration: function name(params) {...}
- Function expression: const name = function(params) {...};
- Arrow function: const name = (params) => {...};
Functions can take parameters, which are variables defined in the function's definition, and arguments, which are the actual values passed to the function when it is called.
Functions can return values using the return statement. If no value is returned, the function implicitly returns undefined.
Functions create their own scope, meaning that variables declared inside a function are not accessible from outside the function.
Higher-order functions are functions that take other functions as arguments or return them. Popular examples include map(), filter(), and reduce().

Description

This quiz covers the non-primitive data types in JavaScript, focusing specifically on arrays and objects. You will learn about their definitions, creation methods, important methods, and how to manipulate their data. Test your knowledge on accessing elements and iterating through these data structures.