index.js

const path = require("path");
const core = require("@actions/core");
const github = require("@actions/github");
const fs = require('fs')

try {
  const finalPackagePath = path.resolve(
    process.env.GITHUB_WORKSPACE,
    core.getInput("versionFilePath")
  );

  if(!fs.existsSync(finalPackagePath)){
    throw new Error(`Version file path not found: ${finalPackagePath}`)
  }

  const packageInfo = require(finalPackagePath);
  if (github.context.payload.ref) {
    const ref = github.context.payload.ref;
    const refVersionParts = ref.split(/\//gi);
    const refVersion = refVersionParts[refVersionParts.length - 1];

    if (packageInfo.version.toLowerCase() !== refVersion.toLowerCase()) {
      core.setFailed(
        `Package version is ${packageInfo.version}, tag version is ${refVersion}`
      );
    } else {
      process.exit(0);
    }
  } else {
    core.setFailed("This action can only be called from a tagged ref");
  }
} catch (err) {
  console.error(err);
  core.setFailed(err.message);
}