E0347: duplicated case clause in switch statement

It's common to copy-paste case clauses when writing switch statements, but this could lead to duplicated expressions in the switch cases by accident. For example, in the code below, there's a duplicated case with the expression '*' when '+' was clearly intended.

function compute(operator, firstNumber, secondNumber) {
  switch (operator) {
    case '*':
      return firstNumber * secondNumber;
    case '-':
      return firstNumber - secondNumber;
    case '*':
      return firstNumber + secondNumber;
  }
}

To fix this warning, we need to replace the expression '*' in the last switch case with the expression '+'

function compute(operator, firstNumber, secondNumber) {
  switch (operator) {
    case '*':
      return firstNumber * secondNumber;
    case '-':
      return firstNumber - secondNumber;
    case '+':
      return firstNumber + secondNumber;
  }
}

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