JavaScript Development KB

Variables & Data Types

Understanding `var`, `let`, `const`, primitive types, and objects.

Operators & Expressions

Arithmetic, assignment, comparison, logical, and ternary operators.

Control Flow

Conditional statements (`if`, `else`, `switch`), loops (`for`, `while`, `do-while`).

Functions

Declaration, expressions, arrow functions, scope, closures, `this` keyword.

Arrow Functions

Concise syntax for functions.

Classes

Syntactic sugar for object-oriented programming.

Template Literals

String interpolation and multi-line strings.

Destructuring Assignment

Extracting values from arrays or properties from objects.

Modules (import/export)

Organizing code into reusable modules.

Promises & Async/Await

Modern ways to handle asynchronous operations.

Callbacks

The traditional way to handle async operations.

Promises

A more structured approach to async code.

const promise = new Promise((resolve, reject) => {
  setTimeout(() => {
    resolve("Operation successful!");
  }, 1000);
});

promise.then(result => console.log(result)).catch(error => console.error(error));

Async/Await

Syntactic sugar over Promises for cleaner async code.

async function fetchData() {
  try {
    const response = await fetch('/api/data');
    const data = await response.json();
    console.log(data);
  } catch (error) {
    console.error("Error fetching data:", error);
  }
}

Selecting Elements

`getElementById`, `querySelector`, `querySelectorAll`.

Modifying Elements

Changing content, attributes, and styles.

Creating & Appending Elements

Using `createElement`, `appendChild`, `insertBefore`.

Event Handling

Listening for user interactions like clicks, input, etc.

document.getElementById('myButton').addEventListener('click', () => {
  alert('Button clicked!');
});

React

A declarative, efficient, and flexible JavaScript library for building user interfaces.

Vue.js

A progressive framework for building user interfaces.

Angular

A platform and framework for building single-page client applications using HTML and TypeScript.

Node.js

A JavaScript runtime built on Chrome's V8 JavaScript engine, used for server-side development.

Browser Developer Tools

Inspect elements, debug JavaScript, monitor network requests.

Linters (ESLint)

Code quality and style enforcement.

Bundlers (Webpack, Vite)

Module bundling and optimization.

Debugging Techniques

`console.log`, `debugger` statement, breakpoints.