modern-spawn

A set of spawn and exec functions that match the API you need 90% of the time in modern applications.

Installation

yarn add modern-spawn

Usage

import {spawnBuffered} from 'modern-spawn';
 
const hello = await spawnBuffered('echo', ['hello world']).getResult('utf8');
 
console.log(hello);

API

export interface Result {
  readonly command: string;
  readonly args: readonly string[] | undefined;
 
  readonly stdout: Buffer;
  readonly stderr: Buffer;
  readonly status: number | null;
 
  getResult(): Buffer;
  getResult(encoding: string): string;
}
 
export interface ResultPromise extends Promise<Result> {
  getResult(): Promise<Buffer>;
  getResult(encoding: string): Promise<string>;
}
 
export interface SpawnBufferedOptions extends SpawnOptions {
  debug?:
    | boolean
    | {
        stdout?: boolean;
        stderr?: boolean;
      };
}
 
export function spawnBuffered(
  command: string,
  args: string[],
  opts?: SpawnBufferedOptions,
): ResultPromise;
 
export function spawnBufferedSync(
  command: string,
  args: string[],
  opts: SpawnBufferedOptions,
): Result;
 
export interface ExecBufferedOptions extends ExecOptions {
  debug?:
    | boolean
    | {
        stdout?: boolean;
        stderr?: boolean;
      };
}
 
export function execBuffered(
  command: string,
  options?: ExecBufferedOptions,
): ResultPromise;
 
export function execBufferedSync(
  command: string,
  options?: ExecBufferedOptions,
): Result;

• getResult can be used to request stdout as either a Buffer or string and automatically throw an error with plenty of context if the process exited with a non-zero status code.
• set debug to true if you want to pipe log stdout & stderr to the parent process for debugging, in addition to buffering it.
• execBufferedSync does returns an empty Buffer for stderr unless the process exits with a non-zero exit code. This is due to a limitation of the node.js API.