Advanced React Calculator

Remember the calculator we made during the in-class lab? Well, let's take it to the next level!

Let's try building an app like the one that comes default on your Mac.

Prerequisites

You will need to know the following concepts before attempting this challenge:

• ES6 Arrow Functions
• React events (such as onClick)
• React State

Steps and Set Up

• Fork and Clone this repository
• Run npm install to install dependencies
• Run npm start to see your basic create-react-app boilerplate
• Implement the requirements below AND one of the bonuses (or more if you have time!)
• Push the code back up to your fork
• Make a pull request against the base fork
• 🎉 Celebrate 🎉

Requirements and Planning Process

You will need to implement the following:

• AC (Clear) button (clear the state)
• 4 main operators + - / * (store operator in state)
• 0-9 buttons (store numerical value in state)
• Equals button (evaluate the answer based on your current state)
• Error messages if the user makes a mistake (such as trying to use two operators)
• A display that shows the current number or current state
  • You can implement it to match the Mac built-in behavior showing the current value only no operator
  • Alternatively you can show the whole equation if you'd like (as on a graphing calculator)
• Basic styling to match the Mac built-in app
  • Orange operator buttons
  • Dark gray display
  • Light gray number buttons

Avoid some potential pitfalls

• Ensure you can use numbers with multiple digits (e.g., can you add 10 + 20?)
  • Make sure you are concatenating each number pressed until you get an operator
• Don't accept 0 as a first number (e.g., 002 should not be allowed)
  • Possible exception - if you implement floating point numbers as part of the bonus, you may have a 0 preceeding the decimal point. Still, while 0.1 is valid, 0000.1 is not, so be sure to only add the 0 in front if the . is pressed first!

Bonus

Choose any of the following:

• Alter your app's logic for the - operator to allow negative numbers to be input
• Implement the +/- button that switches a number from negative to positive or vice versa
• Implement the % button either...
  • As a true modulus operator
  • As a percent button, like it is on the Mac program (just divides current number by 100)
• Implement the floating point . button in order to support decimals.
  • Don't allow more than one decimal per number!