Classifying a branch as master or dev I am dealing constantly with the following code. 

The thing is that literally it makes no sense for me to have all the spacing and divisions in the if-else when the code is so small that can be a block by itself.

When I read a line within line breaks I expect something difficult to understand or something that should be paid special care to be read about. Not just a line break after each function or if definition by default.

if (branchInfo.name === BRANCHNAMES.MASTER) {

    branchInfo.isMaster = true;

} else if (
    branchInfo.name === BRANCHNAMES.RELEASE ||
    branchInfo.name === BRANCHNAMES.HOTFIX
) {

    branchInfo.isDev = true;

}


Given that the line doesn't exceed the 120 characters and that they are small truthy statements that don't deserve to get a function, I want to remove that unnecessary split in the else if because it doesn't seem necessary, almost like the other line breaks and in my opinion it just leads into weird code.

if (branchInfo.name === BRANCHNAMES.MASTER) {
    branchInfo.isMaster = true;
} else if (branchInfo.name === BRANCHNAMES.RELEASE || branchInfo.name === BRANCHNAMES.HOTFIX) {
    branchInfo.isDev = true;
}


Am I being over paranoid about it? Is this actually a good practice?

PS: I know a good practice is to keep into a coding style and always keep it as it is, but really, I can't stand some things that just make code look weird. Sometimes too many line breaks also lead into unreadable code, don't you think so?
Personally, I see no problem doing it either way. I prefer to keep my lines shorter than that but 120ish characters isn't unreasonable.

Another option you have is to store those values in some other variables and use those instead.

let isMaster = branchInfo.name === BRANCHNAMES.MASTER;
let isRelease = branchInfo.name === BRANCHNAMES.RELEASE;
let isHotfix = branchInfo.name === BRANCHNAMES.HOTFIX;
if (isMaster) {
    branchInfo.isMaster = true;
} else if (isRelease || isHotfix) {
    branchInfo.isDev = true;
}


Another way would be to use a switch statement with case fallthrough. Some people refuse to allow fallthrough so it's your call.

switch (branchInfo.name) {
    case BRANCHNAMES.MASTER:
        branchInfo.isMaster = true;
        break;

    case BRANCHNAMES.RELEASE:
    case BRANCHNAMES.HOTFIX:
        branchInfo.isDev = true;
}


Finally, I would consider just assigning directly.

branchInfo.isMaster = branchInfo.name === BRANCHNAMES.MASTER;
branchInfo.isDev = branchInfo.name === BRANCHNAMES.RELEASE ||
                   branchInfo.name === BRANCHNAMES.HOTFIX;


There's also one trick I use if I need to compare against multiple things at once.

let devBranches = [BRANCHNAMES.RELEASE, BRANCHNAMES.HOTFIX];
branchInfo.isMaster = branchInfo.name === BRANCHNAMES.MASTER;
branchInfo.isDev = devBranches.includes(branchInfo.name);


If you don't perform any extra work in either branch of the if statement, I would use the last or second to last option. If you need to perform additional work, I would use the additional variables to make it more readable.