Handle Number Input

Task

Make the calculator accept a digit and store it in state.current.

Open

Open:

js/calculator.js

Add an inputDigit() method inside the Calculator class.

Add the method

inputDigit(digit) {
  if (this.state.waitingForOperand || this.state.justCalculated) {
    this.state.current = digit;
    this.state.waitingForOperand = false;
    this.state.justCalculated = false;
    return;
  }

  if (this.state.current === '0') {
    this.state.current = digit;
    return;
  }

  this.state.current += digit;
}

This method handles three cases:

• A new operand is expected, so the digit replaces the current value.
• The calculator is showing its initial 0, so the digit replaces it.
• Otherwise, the digit is appended to the current value.

Test

In the browser console, try:

calculator.clear();
calculator.inputDigit('5');
calculator.inputDigit('2');
calculator.state.current;

The result should be:

"52"

Then test a new operand:

calculator.state.waitingForOperand = true;
calculator.inputDigit('8');
calculator.state.current;

The result should be:

"8"

Checkpoint

The calculator can now build multi-digit numbers from individual digit inputs.