node-prune/prune.go

// Package prune provides node_modules pruning of unnecessary files.
package prune

import (
	"os"
	"path/filepath"

	"github.com/apex/log"
	"github.com/pkg/errors"
)

// DefaultExtensions pruned.
var DefaultExtensions = []string{
	".md",
	".ts",
}

// Stats for a prune.
type Stats struct {
	FilesTotal   int64
	FilesRemoved int64
	SizeRemoved  int64
}

// Pruner is a module pruner.
type Pruner struct {
	dir  string
	log  log.Interface
	exts map[string]struct{}
}

// Option function.
type Option func(*Pruner)

// New with the given options.
func New(options ...Option) *Pruner {
	v := &Pruner{
		dir:  "node_modules",
		log:  log.Log,
		exts: toMap(DefaultExtensions),
	}

	for _, o := range options {
		o(v)
	}

	return v
}

// WithDir option.
func WithDir(s string) Option {
	return func(v *Pruner) {
		v.dir = s
	}
}

// WithExtensions option.
func WithExtensions(s []string) Option {
	return func(v *Pruner) {
		v.exts = toMap(s)
	}
}

// Prune performs the pruning.
func (p Pruner) Prune() (*Stats, error) {
	var stats Stats

	err := filepath.Walk(p.dir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}

		stats.FilesTotal++

		if !p.prune(path, info) {
			return nil
		}

		if info.IsDir() {
			return filepath.SkipDir
		}

		p.log.WithField("path", path).Debug("prune")
		stats.FilesRemoved++
		stats.SizeRemoved += info.Size()

		if err := os.Remove(path); err != nil {
			return errors.Wrap(err, "removing")
		}

		return nil
	})

	return &stats, err
}

// prune returns true if the file or dir should be pruned.
func (p Pruner) prune(path string, info os.FileInfo) bool {
	if info.IsDir() {
		return false
	}

	ext := filepath.Ext(path)
	_, ok := p.exts[ext]
	return ok
}

// toMap returns a map from slice.
func toMap(s []string) map[string]struct{} {
	m := make(map[string]struct{})
	for _, v := range s {
		m[v] = struct{}{}
	}
	return m
}