Function onEachLine

npm_modules/cli/test/helpers/StreamHelpers.ts:28–37

(
  fn: (line: Buffer) => void,
)

 * The input/output is not changed and cannot be mutated by the callback.
 */
export function onEachLine(
  fn: (line: Buffer) => void,
): (source: AsyncGenerator<Buffer | string>) => AsyncGenerator<string | Buffer> {
  return async function* (source) {
    for await (const line of pipeEachLine(source)) {
      fn(typeof line === 'string' ? Buffer.from(line) : line);
      yield line;
    }
  };
}