The Javascript you need for ReactJS (or Vue, Angular, Node)

Learn how to define variables in JavaScript using let, const, and var, and understand naming rules, data types (numbers, strings, booleans, objects, arrays), and case sensitivity.

Compare let, const, and var to understand scope across global, function, and block contexts. Explore redeclaration, reassignment, and initialization to see how these keywords differ in use.

Learn when to use var, let, and const in JavaScript, explore their block scope and redeclaration rules, and choose based on whether you will update the value to prevent errors.

Learn JavaScript arithmetic: add, subtract, multiply, divide, exponent, modulus, and pre- and post- increment and decrement, plus string concatenation and conditional checks for divisibility.

Explore JavaScript comparison operators to compare values and types, including == vs === and != vs !==, and apply them in if-else and ternary expressions for conditional logic.

Explore assignment operators in JavaScript, including simple assignment, addition assignment, subtraction, multiplication, division, remainder, and exponential assignment, with practical x-based examples.

Explore logical operators in JavaScript, including and, or, and not, evaluate conditions with true or false results, and use ternary expressions and if statements with console logs.

Explore var, let, and const scopes; var is global or function scoped. Use const for values and let for changes, cover remainder, post and pre increments, ternary, and logical operators.

Practice essential JavaScript concepts with exercises on swapping values, computing the difference from 13, summing integers with triple when equal, and checking positive and negative pairs using logical operators.

Explore JavaScript strings as objects, using length and methods like toUpperCase, toLowerCase, replace, concat, and split, and check includes, startsWith, endsWith as you prepare for template literals.

Explore template literals, created with backticks, to include quotes and write multi-line strings. Substitute variables or expressions inside strings, such as two plus two, which evaluates before display.

Master numbers in JavaScript by using toFixed for decimal precision and Number, toString, and parseInt for conversions. Verify types with typeof using examples like 3.456 and 45.3.

Generate random numbers in JavaScript using Math.random and scale to whole numbers. Learn to produce ranges like 0–10 and 5–10 with parseInt, floor, ceil, and min-max adjustments.

Exercises and solutions introduce a runMinMax(min, max) function that returns a random integer between min and max using Math.random, Math.floor, and the range max minus min plus one.

Explore how functions in JavaScript act as building blocks that take inputs, perform tasks, and produce outputs, enabling encapsulation, readability, organization, and reuse.

Learn to declare and use JavaScript functions with the function keyword, function expressions, and arrow functions, and the rest parameter to collect extra arguments into an array.

Explore arrow functions in JavaScript, compare them with traditional function declarations, and learn concise single-line forms that return values, including checking even numbers with modulo and averaging two numbers.

Explore how the return statement stops execution and controls function outputs, using doublet and max examples to show returning values, true/false logic, and how undefined arises without a return.

Explore how functions act as machines that process inputs into outputs, learn different function declarations, use rest parameters like arrays, and see how return stops execution.

Learn to find the maximum of three integers and inputs using rest parameters and Math.max, and to prefix strings with 'JS' when needed, as shown in the exercises and solutions.

Explore how JavaScript treats objects as containers of key-value pairs with properties and methods, and learn to create objects using const, let, or var.

Learn how to access, update, and add object properties in JavaScript using dot and bracket notation, with examples like first name, last name, age, and location.

Learn how object methods work in JavaScript, using dot and bracket notation, invoking functions, and using this to combine first and last names into a full name.

Learn to iterate objects with the for in loop, access keys and values using bracket notation, and dynamically console log properties like first name, last name, and age.

Discover how object destructuring extracts only the needed properties from a person object to nested location data like country and city, for cleaner code and readable output using string interpolation.

Learn how to retrieve an object's keys and values using Object.keys and Object.values on a sample person object with first name, last name, and age.

Explain how objects hold key-value pairs, with values like strings, numbers, arrays, or functions, and access, update, and create properties using dot or bracket notation, this, for-in, destructuring, and Object.keys/Object.values.

Practice manipulating objects in JavaScript by deleting a key and returning a new object, counting properties with for-in, and checking for a property to return true or false.

Explore how arrays hold many values under a single name and are accessed by index numbers starting at zero, unlike objects that use named keys.

Explore JavaScript arrays by using the length property to count items, access first and last elements, and modify with push, pop, shift, and unshift, and use Array.isArray checks.

Learn array destructuring in JavaScript by extracting values from arrays with square brackets, understanding position over name, selecting specific elements, and using destructuring with functions that return arrays.

Explore key array methods in JavaScript: concat to join arrays, join to form strings with a separator, includes to test presence, and slice to extract subarrays without mutating the original.

Use array map to iterate arrays, return transformed values with a callback or arrow function, and build new arrays such as numbers multiplied by two or full names from objects.

Explore how the array filter returns elements that pass a condition, using an arrow function to extract numbers greater than five and strings that include 'a'.

Explore the array.find method in JavaScript, which returns the first element that passes a test, contrast it with filter, and see how to locate objects by id in an array.

Learn how the array reduce method uses an accumulator to loop through elements, with or without an initial value, to compute totals, including a cart total with quantity times price.

Explore how arrays hold multiple values and how to access elements by index. Learn core methods like includes, map, filter, find, and reduce to manipulate and compute results.

practice JavaScript array operations, including reversing with push, unshift, and reverse, extracting first n elements with slice, and adding to a cart with includes checks for duplicates.