Why Do Expressions in Switch Case Statements Not Work as Expected in JavaScript?

Expression Evaluation in Switch Case Statements

In JavaScript, the switch statement evaluates a single expression against a series of constant expressions. However, attempting to use expressions within the case clauses can result in unexpected behavior, as demonstrated in the code snippet provided.

The goal is to use a switch statement to determine a reward based on the value of the amount variable. Expression evaluation is attempted, as seen in the case clauses:

<code class="javascript">case (amount >= 7500 && amount < 10000):
// ...
case (amount >= 10000 && amount < 15000):
// ...

Unfortunately, these expressions evaluate to booleans (true or false) rather than matching the numerical values of amount. As a result, the switch statement will never enter any of the cases.

To address this issue, one possible solution is to use the true expression as the case value and evaluate the expression inside the case clause, like this:

<code class="javascript">switch (true) {
  case (amount >= 7500 && amount < 10000):
    // ...
    break;
  case (amount >= 10000 && amount < 15000):
    // ...
    break;
}</code>

This approach works because the case value is now the boolean true, and the expression in the case clause evaluates to a boolean value.

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