// rollup.config.js
import replace from 'rollup-plugin-replace';

export default {
	// ...
	plugins: [
		replace({
			ENVIRONMENT: JSON.stringify('production')
		})
	]
};

{
  // a minimatch pattern, or array of patterns, of files that
  // should be processed by this plugin (if omitted, all files
  // are included by default)...
  include: 'config.js',

  // ...and those that shouldn't, if `include` is otherwise
  // too permissive
  exclude: 'node_modules/**',

  // To replace every occurrence of `<@foo@>` instead of every
  // occurrence of `foo`, supply delimiters
  delimiters: ['<@', '@>'],

  // All other options are treated as `string: replacement`
  // replacers...
  VERSION: '1.0.0',
  ENVIRONMENT: JSON.stringify('development'),

  // or `string: (id) => replacement` functions...
  __dirname: (id) => `'${path.dirname(id)}'`,

  // ...unless you want to be careful about separating
  // values from other options, in which case you can:
  values: {
    VERSION: '1.0.0',
    ENVIRONMENT: JSON.stringify('development')
  }
}

{
	changed: 'replaced';
}

console.log('changed');
console.log('unchanged');

console.log('replaced');
console.log('unchanged');

{
  changed: 'replaced',
  delimiters: ['', '']
}