Using multiple values in a JS switch case

DanielMay 5, 2021

One thing to mention about the Javascript switch statement is that it continues its flow until it sees a break or a return from that function. It does not automatically ends when a new case statement appears. Conveniently, this solves the problem of matching multiple values.

switch (animal.type) { 
    case "CAT": 
    case "JAGUAR": 
        return "this is a feline";
    case "ALIGATOR": 
        return "this is a reptile";
    default: 
        return "not sure what animal is this"; 
}

The above flow will catch both the CAT and JAGUAR under the same action. This is often used in Redux reducers when updating the state in response to certain actions.