Rollup plugin to rename imports in an ES modules

rollup-plugin-rename-imports.js

/**
 * @example
 * // rename 'preact' as 'https://cdn.pika.dev/preact/^8.5.2'
 * // and set 'https://cdn.pika.dev/preact/^8.5.2' as external
 * renameImports({ 'preact': 'https://cdn.pika.dev/preact/^8.5.2' })
 */
export default function renameImports(packages = {}) {
  return {
    name: 'rename-imports',
    transform(code) {
      for (let npm in packages) {
        const cdn = packages[npm]
        const regex = new RegExp(
          `^import(?:["'\\s]*([\\w*{}\\n, ]+)(from)\\s*)?\\s*(["'\\s]${npm}["'\\s])`,
          'm'
        )
        return code.replace(regex, `import $1$2 '${cdn}'`)
      }
    },
    options(opts) {
      const external = Object.values(packages)
      return Object.assign({}, opts, { external })
    }
  }
}