Why do cases in switch statements in JavaScript not have their own code blocks?

Question

Within JavaScript, I was recently experimenting with switch statements to accomplish some parameter checking in a for-in loop and I found that the syntax does not feel like it is very consistent with the theme of using code blocks in JavaScript.

My example data is the following:

var data = {
    one: "hello",
    two: "world"
}

What I would imagine a switch statement to look like would be:

function isDataRoughlyMyExample(data) {
    if (typeof data !== "object") {
        return false;
    }
    let count = 0;
    for (const name in data) {
        count++;
        switch (name) {
            case "one", "two" {
                if (typeof data[name] !== "string") {
                    return false;
                }
            }
            default {
                return false;
            }
        }
    }
    if (count === 0) {
        return false;
    } else {
        return true;
    }
}

However JavaScript seems to follow the general theme of python by having the code block use the white space for code readability

function isDataRoughlyMyExample(data) {
    if (typeof data !== "object") {
        return false;
    }
    let count = 0;
    for (const name in data) {
        count++;
        stuff: switch (name) {
            case "one":
            case "two":
                if (typeof data[name] !== "string") {
                    return false;
                }
                break stuff;
            default:
                return false;
        }
    }
    if (count === 0) {
        return false;
    } else {
        return true;
    }
}

To clarify, I am asking why switch statements work the way they do. I am aware that it is unlikely to be changed due to JavaScript's love for backwards compatibility, but it does confuse me why it is like this.

Answer 1

That's also how switch works/looks in several other languages (most noteworthy of them being C). So, adding these code blocks would increase confusion, not decrease it.