npm-installed 
Find programs installed by npm
Install
$ npm install --save npm-installed
Usage
var npmInstalled = require('npm-installed');
npmInstalled('imagemin', function (err, path) {
if (err) {
throw err;
}
console.log(path);
//=> /home/sirjohndoe/.npm-packages/bin/imagemin
});
npmInstalled.sync('imagemin');
//=> /home/sirjohndoe/.npm-packages/bin/imagemin
License
MIT © Kevin Mårtensson