installs the given modules if needed
npm install install-if-needed
Installs the given list of modules and saves them into their respective fields in your nearest package.json. Dependencies that already exist in your package.json will be skipped.
``js
var install = require('install-if-needed')
install({
dependencies: ['through2'],
devDependencies: ['tape@2.x', 'standard']
}, function(err) {
if (err)
console.error("There was an error installing.")
})
`
You can pass { stdio: 'inherit' } to preserve logging and colors, acting like the usual npm install command.
#### install(opt[, cb])
Looks at package JSON and installs any of the specified dependencies that are not listed in their respective field.
- cwd the directory for the closest package.json, (default process.cwd())package
- optional package data, if not defined will search for closest package.json
- whether to --save, --save-dev and --save-optional (default true)dependencies
- dependencies to installdevDependencies
- dev dependencies to installoptionalDependencies
- optional dependencies to installcommand
- the command to spawn when installing, defaults to 'npm'
Other options are passed to spawn-npm-install.
On complete, cb is called with (err) status. All dependencies also accept a single string instead of an array.
Alternatively, opt can be a string or array, which is the same as listing it in dependencies.
`js`
//e.g.
// npm install tape --save
install('tape', done)
This helps build CLI tooling that auto-installs modules as needed. For example, a tool which stubs out an empty test file for tape:
`js
#!/usr/bin/env node
var install = require('install-if-needed')
var fs = require('fs')
var template = fs.readFileSync(__dirname + '/template.js')
install({
devDependencies: 'tape'
}, function(err) {
if (err) throw err
fs.writeFile(process.argv[2], template)
})
`
And the CLI might be as simple as:
`sh``
quick-tape tests/simple.js
MIT, see LICENSE.md for details.