Programmatic refactor to prefix all private, protected, and internal class members with an underscore.

prefix-internal-class-members.ts

// This script will look at all the exported class declarations from the main entrypoint of a library
// and ensure all private, protected, and @internal members are prefixed with an underscore.
import { Project, Node, SyntaxKind, TypeGuards, Scope, ClassMemberTypes, ParameterDeclaration } from "ts-simple-ast";

const project = new Project({ tsConfigFilePath: "tsconfig.json" });
const sourceFiles = project.getSourceFiles();

for (const file of sourceFiles)
    for (const classDec of file.getDescendantsOfKind(SyntaxKind.ClassDeclaration))
        for (const member of classDec.getMembers())
            doRenameIfNecessary(member);

project.save();

function doRenameIfNecessary(node: ClassMemberTypes | ParameterDeclaration) {
    // handle constructor parameter properties
    if (TypeGuards.isConstructorDeclaration(node)) {
        node.getParameters().forEach(doRenameIfNecessary);
        return;
    }

    if (node.getScope() !== Scope.Protected && node.getScope() !== Scope.Private && !hasInternalDocTag(node))
        return;
    if (node.getName().startsWith("_"))
        return;

    node.rename("_" + node.getName());
}

function hasInternalDocTag(node: Node) {
    // this checks if the node has an @internal jsdoc tag
    return TypeGuards.isJSDocableNode(node)
        && node.getJsDocs().some(d => d.getTags().some(t => t.getTagName() === "internal"))
}