@semantic-release/changelog/lib/prepare.js

semantic-release plugin to create or update a changelog file

import path from "node:path";
import { readFile, writeFile, mkdir } from "node:fs/promises";
import resolveConfig from "./resolve-config.js";

const ensureFile = async (filePath) => {
  await mkdir(path.dirname(filePath), { recursive: true });
  try {
    await readFile(filePath);
  } catch {
    await writeFile(filePath, "");
  }
};

export default async (pluginConfig, { cwd, nextRelease: { notes }, logger }) => {
  const { changelogFile, changelogTitle } = resolveConfig(pluginConfig);
  const changelogPath = path.resolve(cwd, changelogFile);

  if (notes) {
    await ensureFile(changelogPath);
    const currentFile = (await readFile(changelogPath, "utf8")).trim();

    if (currentFile) {
      logger.log("Update %s", changelogPath);
    } else {
      logger.log("Create %s", changelogPath);
    }

    const currentContent =
      changelogTitle && currentFile.startsWith(changelogTitle)
        ? currentFile.slice(changelogTitle.length).trim()
        : currentFile;
    const content = `${notes.trim()}\n${currentContent ? `\n${currentContent}\n` : ""}`;

    await writeFile(changelogPath, changelogTitle ? `${changelogTitle}\n\n${content}` : content);
  }
};