A minimal package for executing commands
This package was created to provide a minimal way of interacting with child processes without having to manually deal with streams, piping, etc.
$ npm i -S tinyexec
A process can be spawned and awaited like so:
import {x} from 'tinyexec';
const result = await x('ls', ['-l']);
// result.stdout - the stdout as a string
// result.stderr - the stderr as a string
You may also iterate over the lines of output via an async loop:
import {x} from 'tinyexec';
const result = x('ls', ['-l']);
for await (const line of result) {
// line will be from stderr/stdout in the order you'd see it in a term
}
Options can be passed to have finer control over spawning of the process:
await x('ls', [], {
timeout: 1000
});
The options object can have the following properties:
signal
- an AbortSignal
to allow aborting of the executiontimeout
- time in milliseconds at which the process will be forceably killedpersist
- if true
, the process will continue after the host exitsstdin
- another Result
can be used as the input to this processnodeOptions
- any valid options to node's underlying spawn
functionthrowOnError
- if true, non-zero exit codes will throw an errorYou can pipe a process to another via the pipe
method:
const proc1 = x('ls', ['-l']);
const proc2 = proc1.pipe('grep', ['.js']);
const result = await proc2;
console.log(result.stdout);
pipe
takes the same options as a regular execution. For example, you can
pass a timeout to the pipe call:
proc1.pipe('grep', ['.js'], {
timeout: 2000
});
You can kill the process via the kill
method:
const proc = x('ls');
proc.kill();
// or with a signal
proc.kill('SIGHUP');
By default, node's available binaries from node_modules
will be accessible
in your command.
For example, in a repo which has eslint
installed:
await x('eslint', ['.']);
In this example, eslint
will come from the locally installed node_modules
.
An abort signal can be passed to a process in order to abort it at a later
time. This will result in the process being killed and aborted
being set
to true
.
const aborter = new AbortController();
const proc = x('node', ['./foo.mjs'], {
signal: aborter.signal
});
// elsewhere...
aborter.abort();
await proc;
proc.aborted; // true
proc.killed; // true
Calling x(command[, args])
returns an awaitable Result
which has the
following API methods and properties available:
pipe(command[, args[, options]])
Pipes the current command to another. For example:
x('ls', ['-l'])
.pipe('grep', ['js']);
The parameters are as follows:
command
- the command to execute (without any arguments)args
- an array of argumentsoptions
- options objectprocess
The underlying node ChildProcess
. For example:
const proc = x('ls');
proc.process; // ChildProcess;
kill([signal])
Kills the current process with the specified signal. By default, this will
use the SIGTERM
signal.
For example:
const proc = x('ls');
proc.kill();
pid
The current process ID. For example:
const proc = x('ls');
proc.pid; // number
aborted
Whether the process has been aborted or not (via the signal
originally
passed in the options object).
For example:
const proc = x('ls');
proc.aborted; // bool
killed
Whether the process has been killed or not (e.g. via kill()
or an abort
signal).
For example:
const proc = x('ls');
proc.killed; // bool
exitCode
The exit code received when the process completed execution.
For example:
const proc = x('ls');
proc.exitCode; // number (e.g. 1)
tinyexec
aims to provide a lightweight layer on top of Node's own
child_process
API.
Some clear benefits compared to other libraries are that tinyexec
will be much lighter, have a much
smaller footprint and will have a less abstract interface (less "magic"). It
will also have equal security and cross-platform support to popular
alternatives.
There are various features other libraries include which we are unlikely to ever implement, as they would prevent us from providing a lightweight layer.
For example, if you'd like write scripts rather than individual commands, and
prefer to use templating, we'd definitely recommend
zx. zx is a much higher level library which
does some of the same work tinyexec
does but behind a template string
interface.
Similarly, libraries like execa
will provide helpers for various things
like passing files as input to processes. We opt not to support features like
this since many of them are easy to do yourself (using Node's own APIs).