--- /dev/null
+// prune extraneous packages.
+
+module.exports = prune
+
+prune.usage = "npm prune"
+
+var readInstalled = require("read-installed")
+ , npm = require("./npm.js")
+ , path = require("path")
+ , readJson = require("read-package-json")
+ , log = require("npmlog")
+
+prune.completion = require("./utils/completion/installed-deep.js")
+
+function prune (args, cb) {
+ //check if is a valid package.json file
+ var jsonFile = path.resolve(npm.dir, "..", "package.json" )
+ readJson(jsonFile, log.warn, function (er) {
+ if (er) return cb(er)
+ next()
+ })
+
+ function next() {
+ var opt = {
+ depth: npm.config.get("depth"),
+ dev: !npm.config.get("production") || npm.config.get("dev")
+ }
+ readInstalled(npm.prefix, opt, function (er, data) {
+ if (er) return cb(er)
+ prune_(args, data, cb)
+ })
+ }
+}
+
+function prune_ (args, data, cb) {
+ npm.commands.unbuild(prunables(args, data, []), cb)
+}
+
+function prunables (args, data, seen) {
+ var deps = data.dependencies || {}
+ return Object.keys(deps).map(function (d) {
+ if (typeof deps[d] !== "object"
+ || seen.indexOf(deps[d]) !== -1) return null
+ seen.push(deps[d])
+ if (deps[d].extraneous
+ && (args.length === 0 || args.indexOf(d) !== -1)) {
+ var extra = deps[d]
+ delete deps[d]
+ return extra.path
+ }
+ return prunables(args, deps[d], seen)
+ }).filter(function (d) { return d !== null })
+ .reduce(function FLAT (l, r) {
+ return l.concat(Array.isArray(r) ? r.reduce(FLAT,[]) : r)
+ }, [])
+}