Bumpversion example

bump.js

fs = require('fs');
// pega o primeiro argumento do script
v = process.argv[1];
// pega o conteúdo do arquivo changelog
changelog = fs.readFileSync('CHANGELOG.md').toString();
// substitui a linha que contem Next Release e a linha inferior
// pela variável v seguida de traços
c = changelog.replace(/(Next Release\\n-+)/i, '\\$1'+'\\n\\n'+v+'\\n'+'-'.padStart(v.length, '-'));
// escreve o resultado no arquivo changelog
fs.writeFileSync('CHANGELOG.md', c);

CHANGELOG-after.md

CHANGELOG

1.1.0

• The next big thing

1.0.1

• A bug was fixed :(

1.0.0

• First release

CHANGELOG-before.md

CHANGELOG

Next Release

• The next big thing

1.0.1

• A bug was fixed :(

1.0.0

• First release

package-example1.json

{
  "scripts": {
    "preversion": "npm test",
    "version": "npm run build && git add -A dist",
    "postversion": "git push && git push --tags && rm -rf build/temp"
  }
}

package.json

{
  "scripts": {
    "release:update-changelog": "node -e \"v=process.argv[1]; fs = require('fs'); c = fs.readFileSync('CHANGELOG.md').toString().replace(/(Next Release\\n-+)/i, '\\$1'+'\\n\\n'+v+'\\n'+'-'.padStart(v.length, '-')); fs.writeFileSync('CHANGELOG.md', c); console.log(c);\"",
    "preversion": "npm run release:update-changelog ${npm_package_version}"
  }
}