Since we are now only building Babel on Node.js 14 (even if we still test it on Node.js 6), we can use native ECMAScript modules for the build scripts:

• Top-level scripts
  There are a bunch of scripts/tests in the scripts folder: they can probably all be rewritten to ES modules.
  We can probably add "type": "module" to the top

Currently PiranhaSwift APIs are specified using a properties file as shown here. It will be helpful to migrate this to use a json file so that more properties can be specified easily. For instance, it could be an array of methodProperties where the methodName, flagType, returnType and argumentIndex of the flag are s

Is your feature request related to a problem? Please describe.

No MappedTypeNode definition in ts-morph.
No TypeQueryNode definition in ts-morph.
No TypeOperatorNode definition in ts-morph.

Looking at CtModifiable class, there a lot of convenience method, but isTransient is missing? Is there any reason for it?
A implementation could be the following.

public boolean isTransient() {
return this.hasModifier(ModifierKind.TRANSIENT);
}

http://spoon.gforge.inria.fr/mvnsites/spoon-core/apidocs/spoon/reflect/declaration/CtModifiable.html

Edit: I looks like some mo