Prettier 2.4.1
Playground link

--parser typescript

Input:

@test().x('global').y()
class X {}

Output:

@(test().x("global").y())
class X {}

Expected behavior:

@test().x('global').y()
class X {}

In TypeScript, the two decorator usages (Input and Output above) are same. They will be compiled to JS like:

let X = class X {
};
X = __decorate([
    // from the input
    test().x('global').y()
    // and from the output. they are same
    (test().x('global').y())
], X);

But the Input's style (no parentheses) is easier to read and looks better. I found a related PR #5785 caused the issue.

Maybe Prettier should support parser based format behavior or parser based config? Only babel should add parentheses for decorators but typescript not.