- 01Setting Up (What You'll Need)
- 02Creating Variables
- 03Conditionals (if Statements)
- 04Loops (for Statements)
- 05Creating Functions
- 06Working with Arrays
- 07Working with Objects
- 08Loops (while Statements)
- 09Working with Strings
- 10Using Classes (Object-Oriented Programming)
- 11Error Handling (try...catch)
- 12Destructuring and the Spread Syntax
- 13Async Code (Promise / async & await)
- 14Advanced Array Methods (filter and reduce)
- 15The switch Statement
- 16The Ternary Operator
- 17Inheritance (Extending Classes)
- 18How to Write Comments
- 19Logical Operators (AND, OR, NOT)
- 20Constants (Making Read-Only Values with const)
- 21Splitting and Joining Strings (split and join)
- 22Null-Safe Syntax (?? and ?.)
- 23Searching Arrays and Collections (includes and find)
- 24Transforming Arrays with map
- 25Two-Dimensional Arrays (Table-Shaped Data)
- 26Building a Custom Error Class
- 27Default Arguments (Setting Initial Values for Parameters)
- 28Using Set (Collections)
- 29Verifying Correctness with assert (Your First Step Into Testing)
- 30Higher-Order Functions (Passing a Function as an Argument)
- 31Stacks and Queues (Basic Data Structures)
- 32The Basics of Type Conversion (Casting)
- 33Introduction to Regular Expressions (Pattern Matching)
- 34The Binary Search Algorithm
- 35Building a Caesar Cipher (a Letter-Shifting Cipher)
- 36Understanding How Bubble Sort Works
- 37Building and Displaying Dates (Basic Year/Month/Day Operations)
- 38Writing Several Unit Tests Together (Multiple Test Cases)
- 39Speeding Up Calculations with Memoization (Caching)
- 40Normalizing Strings (trim and Case Unification)
- 41The Difference Between Shallow Copy and Deep Copy
- 42The Basics of Enums (Enumerated Types)
- 43Flattening Arrays (flatten)
- 44Reversing a String and Checking for a Palindrome
- 45Pairing Up Two Arrays (a zip Operation)
- 46Rounding Numbers (floor, ceil, and round)
- 47Multi-Line Strings (Template Literals)
- 48Returning Multiple Values from a Function (Array Destructuring)
- 49Finding the GCD and LCM (the Euclidean Algorithm)
- 50Formatting Numbers (Digit Alignment and Decimal Precision)
- 51Cleanup Processing with try/catch/finally
- 52Writing Type-Agnostic, General-Purpose Functions
- 53The Basics of Map (an Object for Key-Value Pairs)
- 54Generating Random Numbers
- 55Bitwise Operations (AND, OR, XOR, and Shift Operations)
- 56Using static (Static Class Properties and Methods)
- 57Waiting a Fixed Amount of Time (setTimeout and await)
- 58Watch Out for Floating-Point Rounding Error
- 59Transforming and Flattening at Once with flatMap()
- 60FizzBuzz (the Classic Practice Problem)
- 61Checking Whether a Number Is Prime
- 62Set Operations with Set (Union, Intersection, and Difference)
- 63Converting Number Bases (Binary and Hexadecimal)
- 64Checking That Brackets Match (an Application of Stacks)
- 65Checking for an Anagram
- 66Checking Whether a Year Is a Leap Year
- 67Converting Temperature (Celsius ⇄ Fahrenheit)
- 68Finding the Prime Factorization
- 69[Applied] Build a Simple To-Do List Tool
Building and Displaying Dates (Basic Year/Month/Day Operations)
In this lesson you'll learn the basics of date manipulation using JavaScript's Date object, so you can correctly build and display a year, month, day, and day of the week. This is for people searching "JavaScript Date usage" or "JavaScript how to get a date."
The Date object lets you build and work with a specific calendar date. As in new Date(year, month-1, day), remember that months are counted starting from 0 (0 for January). This quirky detail is one of the most common beginner stumbling blocks. You can pull out each piece of information with methods like .getFullYear(), .getMonth(), .getDate(), and .getDay().
The sample code uses new Date(2026, 7, 9) to create a date object representing August 9, 2026, and converts .getMonth() + 1 back into the actual month number. .getDay() returns the day of the week as a number from 0 (Sunday) to 6 (Saturday), so it's combined with an array of weekday names to display "Sun, Mon, Tue, Wed, Thu, Fri, Sat."
A common beginner stumbling block is forgetting that months are counted from 0, and building a date that's a month off from what was intended. A mistake like "wanting to create August but specifying 8 instead of 7, ending up with September" happens very often, so always keep "month minus 1" in mind. Also be careful that how time is handled can vary by time zone.
This is essential basic knowledge for any app dealing with dates, such as a reservation system or an event calendar, and it's also frequently used for calculations involving the day of the week. It's foundational knowledge you can't do without when building your own reservation system or calendar feature.
💡 Anything passed to console.log() appears in the output below.