JavaScript Fundamentals

Syntax

• Variables: declared using let, const, or var keywords
• Data Types:
  • Primitive: number, string, boolean, null, undefined
  • Complex: object, array, function
• Operators:
  • Arithmetic: +, -, *, /, %, etc.
  • Comparison: ===, !==, >, <, >= , <=
  • Logical: &&, ||, !
• Control Structures:
  • Conditional: if/else, switch
  • Loops: for, while, do...while
  • Functions: function keyword, => arrow function

Event Handling

• Events: user interactions (e.g., clicks, key presses) or browser events (e.g., page load)
• Event Listeners: functions attached to elements to handle events
• addEventListener: method to attach an event listener to an element
• Event Object: provides information about the event (e.g., target, type, timestamp)

Async Programming

• Asynchronous: code that runs concurrently with other tasks
• Callbacks: functions passed as arguments to other functions to handle async results
• Promises: objects that represent async operations and their results
• Async/Await: syntax sugar for working with promises
• ** setTimeout**: method to schedule a function to run after a delay

DOM Manipulation

• Document Object Model (DOM): tree-like representation of HTML documents
• Elements: nodes in the DOM tree
• Selecting Elements: using document.getElementById, document.querySelector, etc.
• Creating Elements: using document.createElement
• Manipulating Elements: using innerHTML, textContent, appendChild, etc.

Object-oriented Programming

• Objects: collections of key-value pairs
• Properties: key-value pairs within an object
• Methods: functions within an object
• Inheritance: creating new objects based on existing ones
• Prototypal Inheritance: JavaScript's inheritance model
• Constructor Functions: functions that create objects when called with new keyword

Syntax

• Variables are declared using let, const, or var keywords
• There are two main categories of data types: primitive and complex
• Primitive data types include number, string, boolean, null, and undefined
• Complex data types include object, array, and function
• Arithmetic operators include +, -, *, /, %, etc.
• Comparison operators include ===, !==, >, and <

Event Handling

• Events are user interactions (e.g., clicks, key presses) or browser events (e.g., page load)
• Event listeners are functions attached to elements to handle events
• The addEventListener method is used to attach an event listener to an element
• The Event Object provides information about the event, including target, type, and timestamp

Async Programming

• Asynchronous code runs concurrently with other tasks
• Callbacks are functions passed as arguments to other functions to handle async results
• Promises are objects that represent async operations and their results
• Async/Await is a syntax sugar for working with promises
• The setTimeout method is used to schedule a function to run after a delay

DOM Manipulation

• The Document Object Model (DOM) is a tree-like representation of HTML documents
• Elements are nodes in the DOM tree
• Elements can be selected using document.getElementById, document.querySelector, etc.
• New elements can be created using document.createElement
• Elements can be manipulated using innerHTML, textContent, appendChild, etc.

Object-oriented Programming

• Objects are collections of key-value pairs
• Properties are key-value pairs within an object
• Methods are functions within an object
• Inheritance is the process of creating new objects based on existing ones
• JavaScript uses a prototypal inheritance model
• Constructor functions are functions that create objects when called with the new keyword