Double semicolons in interface after insert

[ericmatthys]

This can be reproduced using https://astexplorer.net/ and the sample code below. This is my first time using jscodeshift, so I may be holding something wrong. If I strip out all the semicolons from the source, then oddly it works and inserts only a single semicolon for all them.

example.ts

export interface Test {
  A: string;
  D: string;
  F: string;
  R: string;
  X: string;
}

transformer.js

// jscodeshift can take a parser, like "babel", "babylon", "flow", "ts", or "tsx"
// Read more: https://github.com/facebook/jscodeshift#parser
export const parser = "tsx";

const nameToAdd = "O";

// Press ctrl+space for code completion
export default function transformer(file, api) {
  const j = api.jscodeshift;
  const root = j(file.source);

  let hasAdded = false;

  const names = root
    .find(j.TSInterfaceDeclaration, { id: { name: "Test" } })
    .find(j.TSPropertySignature)
    .find(j.Identifier);

  names.forEach((path, i) => {
    if (path.value.name === nameToAdd) {
      hasAdded = true;
    }

    if (hasAdded) {
      return;
    }

    if (path.value.name.localeCompare(nameToAdd) > 0) {
      hasAdded = true;
      path.parentPath.insertBefore(`${nameToAdd}: string`);
    } else if (i + 1 === names.length) {
      hasAdded = true;
      path.parentPath.insertAfter(`${nameToAdd}: string`);
    }
  });

  return root.toSource();
}

Output

export interface Test {
  A: string;;
  D: string;;
  F: string;;
  O: string;
  R: string;;
  X: string;;
}