Here are some mini-project ideas that you can build using JavaScript:

To-do List: Create a simple to-do list app where users can add, edit, and delete tasks.

Calculator: Build a basic calculator app that performs basic arithmetic operations like addition, subtraction, multiplication, and division.

Timer: Create a countdown timer that displays the time remaining and allows users to start, pause, and reset the timer.

Random Quote Generator: Use an API to fetch a random quote and display it on the page. Allow users to generate new quotes by clicking a button.

Weather App: Build a weather app that displays the current weather conditions for a user's location or a specified location.

BMI Calculator: Create a BMI (Body Mass Index) calculator that allows users to enter their height and weight and calculates their BMI.

Pomodoro Timer: Create a Pomodoro timer that helps users focus by breaking their work into intervals of 25 minutes with 5-minute breaks in between.

Password Generator: Build a password generator that creates random passwords based on user-specified criteria like length, complexity, and character types.

Memory Game: Create a memory game where users have to match pairs of cards with identical images.

Hangman Game: Build a hangman game where users have to guess a secret word by selecting letters one by one.

Quiz App: Create a quiz app that allows users to select a topic and answer a series of multiple-choice questions.

Music Player: Build a basic music player app that allows users to play, pause, and skip songs.

Image Slider: Create an image slider that displays a series of images and allows users to navigate between them.

Calendar: Build a simple calendar app that displays the current month and allows users to view upcoming events.

Expense Tracker: Create an expense tracker app that allows users to track their income and expenses and displays their balance.

Typing Speed Tester: Build a typing speed tester that calculates the user's typing speed and accuracy.

Countdown Timer: Create a countdown timer that displays the time remaining until a specific date and time.

Random Password Generator: Build a random password generator that creates secure passwords using a combination of letters, numbers, and symbols.

Snake Game: Create a classic snake game where users control a snake that grows in length as it eats food.

Memory Card Game: Build a memory card game where users have to match pairs of cards with identical images, but with a time limit.

Currency Converter: Build a currency converter app that allows users to convert between different currencies based on the current exchange rates.

Movie Recommendation Engine: Create a movie recommendation engine that suggests movies to users based on their preferences and ratings.

Hangman Game with Images: Build a hangman game that displays an image of the secret word and allows users to guess the letters.

Restaurant Menu: Create a restaurant menu that displays the menu items and allows users to select and order their food.

Rock, Paper, Scissors Game: Build a simple rock, paper, scissors game where users can play against the computer.

Tic Tac Toe Game: Create a tic tac toe game where users can play against each other or against the computer.

Drawing App: Build a drawing app that allows users to draw and paint using different colors and tools.

Chess Game: Create a chess game that allows users to play against the computer or against other players online.

Random Name Generator: Build a random name generator that creates unique names based on user-specified criteria like gender, ethnicity, and length.

Memory Game with Sounds: Create a memory game where users have to match pairs of cards with identical sounds.

Hangman Game with Hints: Create a hangman game that allows users to get hints about the secret word.

Todo List: Build a todo list app that allows users to create, edit, and delete tasks.

Digital Clock: Create a digital clock that displays the current time and date.

Pomodoro Timer: Build a pomodoro timer app that allows users to track their work and break sessions.

Weather Forecast: Create a weather forecast app that displays the current weather and temperature for a specified location.

Calculator: Build a basic calculator app that allows users to perform arithmetic operations.

Password Strength Checker: Create a password strength checker that evaluates the strength of user passwords based on length, complexity, and other factors.

Drawing Pad: Build a drawing pad app that allows users to draw and paint using different colors and brushes.

RSS Reader: Create an RSS reader that displays the latest news and updates from specified RSS feeds.

Interactive Quiz Game: Build an interactive quiz game that displays a series of questions and allows users to select their answers.

Text Adventure Game: Create a text adventure game where users can navigate through a story by selecting different options.

Sudoku Game: Build a sudoku game that allows users to play and solve sudoku puzzles.

Card Matching Game: Create a card matching game where users have to match pairs of cards with identical images.

Simon Game: Build a Simon game that tests users' memory and ability to repeat a sequence of sounds.

Analog Clock: Create an analog clock that displays the current time using hour, minute, and second hands.

Recipe Book: Build a recipe book app that displays recipes and allows users to search and filter by ingredients and cuisine.

Shopping Cart: Create a shopping cart app that allows users to add and remove items from their cart and calculates the total price.

Instagram Clone: Build a simplified version of the popular social media app Instagram, where users can upload and view photos.

Chat Application: Create a chat application that allows users to send and receive messages in real-time.

Breakout Game: Build a classic breakout game where users control a paddle to hit a ball and break bricks.