A modern programming language that makes developers happier.

kotlinlang

Do people typically add `is` at the start of a boolean name in kotlin?

Basically need to create a bool called `isDebug` but arguing with myself if it should be `debug` or `isDebug` .

To follow the example set by the designers of Kotlin: if a Java boolean method is called `isDebug()` then Kotlin creates a property called `isDebug`. So, yes, add the `is` prefix.

no, not as a rule. Sometimes `is` as a prefix makes sense (in order to make code read more expressively) but using it indiscriminately is basically just Hungarian notation with extra steps

say you want to add a `debug` flag to some kind of config, then you go to use it, which results in the callsite looking like this

```if (config.isDebug) {
  ...
}```
which reads like “if the config is debug, then…“, which doesn’t really make a whole lot of sense. You might try to make it a bit more descriptive like this
```if (config.isDebugMode)```
but really, I think that just makes it obvious that you should omit `is` in this case, and just write something like this
```if (config.debugEnabled)```
I’d try to reserve usage of `is` in cases where the boolean describes the state of its container or otherwise actually makes a conditional read more sensibly

what about java interop? calling the property `debug` generates a method `getDebug()`, calling it `isDebug` generates `isDebug()` . depending on what library you use (or is you want your library to be used in java) I think the second convention is more solid (naming convention for boolean getters is - or at least was, honestly not sure anymore - `isMyBool`)

Another common prefix is `has`  as in `Node.hasChildren`. So I'd say it depends a bit on your preference and whether you want the special Java interop or not.