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@npmcli/promise-spawn
Spawn processes the way the npm cli likes to do. Give it some options, it'll give you a Promise that resolves or rejects based on the results of the execution.
USAGE
const promiseSpawn = require('@npmcli/promise-spawn')
promiseSpawn('ls', [ '-laF', 'some/dir/*.js' ], {
cwd: '/tmp/some/path', // defaults to process.cwd()
stdioString: true, // stdout/stderr as strings rather than buffers
stdio: 'pipe', // any node spawn stdio arg is valid here
// any other arguments to node child_process.spawn can go here as well,
}, {
extra: 'things',
to: 'decorate',
the: 'result',
}).then(result => {
// {code === 0, signal === null, stdout, stderr, and all the extras}
console.log('ok!', result)
}).catch(er => {
// er has all the same properties as the result, set appropriately
console.error('failed!', er)
})
API
promiseSpawn(cmd, args, opts, extra)
-> Promise
Run the command, return a Promise that resolves/rejects based on the process result.
Result or error will be decorated with the properties in the extra
object. You can use this to attach some helpful info about why the
command is being run, if it makes sense for your use case.
If stdio
is set to anything other than 'inherit'
, then the result/error
will be decorated with stdout
and stderr
values. If stdioString
is
set to true
, these will be strings. Otherwise they will be Buffer
objects.
Returned promise is decorated with the stdin
stream if the process is set
to pipe from stdin
. Writing to this stream writes to the stdin
of the
spawned process.
Options
stdioString
Boolean, defaulttrue
. Return stdout/stderr output as strings rather than buffers.cwd
String, defaultprocess.cwd()
. Current working directory for running the script. Also the argument toinfer-owner
to determine effective uid/gid when run as root on Unix systems.shell
Boolean or String. If false, no shell is used during spawn. If true, the system default shell is used. If a String, that specific shell is used. When a shell is used, the given command runs from within that shell by concatenating the command and its escaped arguments and running the result. This option is not passed through tochild_process.spawn
.- Any other options for
child_process.spawn
can be passed as well.
promiseSpawn.open(arg, opts, extra)
-> Promise
Use the operating system to open arg
with a default program. This is useful
for things like opening the user's default browser to a specific URL.
Depending on the platform in use this will use start
(win32), open
(darwin)
or xdg-open
(everything else). In the case of Windows Subsystem for Linux we
use the default win32 behavior as it is much more predictable to open the arg
using the host operating system.
Options
Options are identical to promiseSpawn
except for the following:
command
String, the command to use to open the file in question. Default is one ofstart
,open
orxdg-open
depending on platform in use.