In lang/javascript there is increase of indents for the first declared property, and then it stays the same you can try it at Try CodeMirror and just type:
And you would see indentation of prop2 is increased comparing with prop1, is it intentional?
And how to change that so no other indentations would break?
Those aren’t properties, they are labeled statements. Put your object in expression context (wrap it in parentheses or put let x = in front) and this should improve.