npm-which

$3


Use npm-which to locate executables which may be installed in the
local 'node_modules/.bin', or in a parent 'node_modules/.bin' directory.

npm-which runs in the context of an npm lifecycle script with its npm-modified PATH.

i.e. if you install a module that has an executable script using npm install, that module's executable will be picked up by npm-which from anywhere in the ./node_modules tree.

Installation

``bash
> npm install -g npm-which
`

Usage

$3

npm-which will find executables relative to the cwd you supply.
The cwd is required in order to be explicit and reduce confusion when
things that should be found are not.

#### Asynchronous

`js
var which = require('npm-which')(process.cwd()) // remember to supply cwd
which('tape', function(err, pathToTape) {
if (err) return console.error(err.message)
console.log(pathToTape) // /Users/.../node_modules/.bin/tape
})
`

#### Synchronous

`js
var which = require('npm-which')(__dirname) // __dirname often good enough
var pathToTape = which.sync('tape')
console.log(pathToTape) // /Users/.../node_modules/.bin/tape
`

#### Options

Both async and sync versions take an optional options object:

* Set options.env if you wish to use something other than process.env (the default)
* Set options.cwd to supply the cwd as a named argument. Mainly for semi-backwards compatibility with npm-which 1.0.0.

`js
which('tape', {cwd: '/some/other/path'}, function() {
// ...
})
`

$3

`bash
> npm-which tape
/Users/timoxley/Projects/npm-which/node_modules/.bin/tape
`

This is the equivalent of running an npm script with the body: which tape.

$3

`bash


unless something is installed in a node_modules

npm-which and which(1) will have the same output:

> which tape
/usr/local/bin/tape

> npm-which tape
/usr/local/bin/tape

install tape local to current dir

tape includes an executable 'tape'

> npm install tape
> ./node_modules/.bin/tape && echo 'found'
found

vanilla which(1) still finds global tape

> which tape
/usr/local/bin/tape

npm-which finds locally installed tape :)

> npm-which tape
/Users/timoxley/Projects/npm-which/node_modules/.bin/tape
`

Why

#### npm is slow to boot

* Shelling out to npm bin is very slow; it has to wait for all of npm to boot up – this often takes longer than the actual script you want to execute!

#### Hard-coding paths to modules is very fragile

* You can't rely on './node_modules' actually containing your module! The module may exist much higher in the directory hierarchy.
* npm bin returns the location of the ./node_modules/.bin` directory, but it does not take into account being called within the context of another module, also, npm slow.
* If the module does exist in a parent directory, then './node_modules/.bin' will be missing your module's executable.

License

MIT