intermock--mock-type-tag.ts

import * as ts from "typescript";

const sourceFile = ts.createSourceFile(
  "example.ts",
  `
interface Host {
  /**
   * @mockType {internet.ipv6}
   */
  addr: string;
  foo: {
    bar: number;
    qux: {
      /**
       * @mockType {internet.ipv4}
       */
      addr2: string;
    }
  };
}`,
  ts.ScriptTarget.ESNext,
  false,
  ts.ScriptKind.TS
);

const visit = <T>(n: ts.Node, f: (n: ts.Node) => T[]): T[] => {
  const results = f(n);
  n.forEachChild(n => {
    results.push(...visit(n, f));
  });

  return results.filter(Boolean);
};

interface PropertySignatureWithJSDoc extends ts.PropertySignature {
  jsDoc: ts.JSDoc[];
}

const collectMockTypes = (n: ts.Node) => {
  if (n.kind === ts.SyntaxKind.PropertySignature && 'jsDoc' in n) {
    const propertySignature = n as PropertySignatureWithJSDoc;
    return propertySignature.jsDoc.flatMap(doc => {
      if (doc.tags) {
        return doc.tags
          .filter(tag => tag.tagName.text === "mockType")
          .map(tag => {
            return {
              name: propertySignature.name.getText(sourceFile),
              mockType: tag.comment,
            };
          });
      }
      return [];
    });
  }
  return [];
};

console.log(visit(sourceFile, collectMockTypes));