JavaScript Fundamentals for Beginners

Master JavaScript strings by declaring strings with double, single, or backticks, and joining text using concatenation or template literals. Learn string interpolation with ${name} and see how expressions evaluate.

Master string handling in JavaScript by escaping quotes with backslashes or using single quotes or backticks. Learn length, charAt, toUpperCase, toLowerCase, and startsWith.

Use browser dev tools to create and run code snippets in the sources workspace, with a built-in code editor and watch panel to monitor console outputs.

Master the JavaScript number data type, covering integers and floating point values, arithmetic, modulo, precedence, and simple comparisons. Practice increment and decrement with count updates.

Learn to convert strings to numbers with parse float and parse int, handle NaN, format with toString and toFixed, and grasp floating point limits and infinity in JavaScript.

Define booleans as a data type that stores true and false and use comparisons on numbers. Explore and, or, not, and truthy and falsy values via double negation in JavaScript.

Explain undefined and null as JavaScript values signaling missing data; undefined means declared but not assigned, while null signifies intentional absence and serves as a placeholder for a future value.

Use the typeof operator to reveal a value’s data type, with examples like 42 as number and true as boolean, including null as object and NaN as number, primitive types.

Learn to convert values to strings in JavaScript using toString, the string constructor, and template literals. Convert numbers and booleans to strings, and embed expressions with template literals.

Convert strings to numbers with the Number constructor and unary plus, using 123, 123.24, and an empty string that becomes 0, and observe not a number outcomes with invalid inputs.

Discover truthy and falsy values in JavaScript and how to convert booleans to numbers or strings, using empty strings, zero, null, undefined, and NaN as falsy values.

Learn how automatic conversions occur in string contexts with the plus operator, where non-string values become strings. Safer concatenation avoids not-a-number results when inputs may be invalid.

Explore how the loose equality operator compares values by converting types, with examples like 5 == '5' and true == 1, and learn the pitfalls of automatic type coercion.

Convert strings to numbers, booleans, and floats in JavaScript, use parse int and parse float, convert true/false, and handle empty or space strings as zero.

Predict JavaScript type coercion outcomes for expressions mixing numbers, strings, booleans, and null. Understand how plus, minus, times, and division convert values, including concatenation and pixels.

Explore JavaScript objects as a fundamental data type, learn to create an employee object with name and age, and access properties using dot, bracket, and destructuring.

Explore JavaScript objects, manipulating properties with dot and bracket notation, adding and deleting fields, nesting objects like supervisor, and handling null or undefined errors.

Explore JavaScript object methods such as hasOwnProperty, Object.keys, Object.values, Object.entries, and Object.freeze, using bartender and waitress examples to check properties, list keys and values, and immutably freeze objects.

Explore the JavaScript math object, which provides constants and functions for calculations, including max, min, random, floor, round, ceil, and pi.

Learn to create and manipulate dates in JavaScript with the date object, using new Date, get full year, get month, get date, toLocaleDateString, set full year, and getTime for comparisons.

manage student data with JavaScript objects by creating alice and bob records, copying with spread operator and Object.assign, parsing JSON for charlie, scheduling lessons, and freezing data.

Learn how to declare and manipulate arrays in JavaScript, access elements by index, check lengths, modify values, and clear lists, with practical grocery list examples.

Merge arrays using the spread operator or concat to form a single grocery list from fruits, vegetables, and dairy, expanding elements while the original lists remain unchanged.

Master filtering arrays in JavaScript using the filter method, arrow functions, and conditions to select items by start letter, length, even/odd quantity, and total quantity, with practical grocery list examples.

Explore how to join array elements into a string with a separator or the default comma, and how to accumulate values with reduce to calculate totals in JavaScript.

Explore multidimensional arrays in JavaScript, including 2d grids and matrices; access and modify elements by row and column, then flatten with flat and reduce for sums.

Master conditional control flow with the if…else statement in JavaScript, learning truthy and falsy values, else if chains, and practical examples like buying a drink.

Practice if else in JavaScript by evaluating a score against grading criteria from highest to lowest and printing the grade with console log, using example scores like 95 and 50.

Explore the switch statement in JavaScript, where the switch evaluates an expression against case values using a calculator example, with break to prevent fall-through and a default for unmatched cases.

Practice switching on a month to determine a season using switch cases, with winter, spring, summer, and fall, and an invalid month default plus console logging the result.

Practice the ternary operator to classify numbers as even or odd, implement login status checks with conditional output, and categorize numbers into negative, zero, positive small, and positive large.

Master the for loop in JavaScript by counting from 1 to 5, exploring initialization, condition, and increment, debugging with breakpoints, and iterating over arrays such as fruits.

Explore the while loop in JavaScript, a flexible control structure for executing code while a condition holds. Print 1 to 5, iterate arrays, and prevent infinite loops.

Practice a while loop by summing numbers from 1 to 10. Initialize number at 1 and sum at 0, loop while number <= limit, then log the final sum 55.

This lecture explains how the for...in loop iterates over enumerable object properties, using a person example and filters by string values, and notes its limited use with arrays.

Practice the for...in construct by iterating a books array with a traditional for loop, then use for...in to enumerate each book's properties and log keys and values.

Master the for..of loop to iterate over arrays, strings, maps, and other iterables without manual counters. Learn through examples with fruit arrays, character iteration, and user objects to print messages.

Practice the for...of construct to print even numbers from an array and to sum each row of a matrix using a nested loop.

Learn how to use break and continue in JavaScript to control loop flow and exit loops early. Skip iterations and apply these concepts in practical examples.

Practice break and continue in JavaScript with a for...of loop over numbers 1 to 10, skip multiples of 3 and stop after seven, logging 1, 2, 4, 5, and 7.

Learn how to declare and call functions with parameters and return values, using an online pet shop to greet customers and count cart items.

pause the video to attempt the exercise, then review an example solution that defines a sum function returning a plus b and tests with console logs for several inputs.

Explore JavaScript scopes by distinguishing global, local, and block scope; learn how variable placement affects accessibility with examples of a shop name accessible inside a function, outside, and within blocks.

Explore let and const in depth, covering block scope, updating and redeclaring inside and outside blocks, and how const preserves references such as arrays or objects while preventing reassignment.

Explore the var keyword in JavaScript, its global and function scope, and why modern JavaScript favors let and const to avoid redeclaration and block scope bugs.

Practice implementing spread and rest parameters in JavaScript by building a function that sums prices with a tax rate, using rest prices and a spread array in tests.

Learn default and optional parameters in JavaScript for beginners by building greet customer and apply discount functions with loyalty levels, discount rates, and coupons.

Use the nullish coalescing operator to assign default values when inputs are null or undefined, avoiding falsy pitfalls of or, with examples like defaulting items per page and greeting users.

Practice the nullish coalescing operator in an exercise by building a pet profile function with defaults for nickname and favorite toy, and observe handling of null versus empty strings.

Explore objects and methods in JavaScript by building a shopping cart object with an items array, add item and list items methods, using this to reference the object.

Practice closures by building a multiplier factory and a validator that checks if numbers are between a minimum and maximum. Learn how lexical scope powers functions to remember these parameters.

Explore JavaScript callbacks by wiring a greeting function to a user input flow using prompt and alert, and learn how callbacks enable asynchronous actions and flexible functions.

Practice callbacks by building processString with a callback, prompting for input, and displaying results; implement toUpperCase and reverseString with split, reverse, and join, then test with hello and world.

Explore immediately invoked function expressions (IIFEs) to create private scopes, execute code instantly, pass arguments, and prevent global pollution in JavaScript.

Learn to edit movie details in a watch list using a function with optional parameters, preserve existing values with null coalescing, and toggle the watched flag safely.

Learn to search for a movie by name in a watch list using case-insensitive matching, display its details, and view all movies by refactoring into a shared print function.

Implement a JavaScript feature to filter movies by all, watched, or unwatched using a switch and array filter, then display results with a print movie details function.