Add "hugo mod npm pack"

This commit also introduces a convention where these common JS config files, including `package.hugo.json`, gets mounted into:

```
assets/_jsconfig
´``

These files mapped to their real filename will be added to the environment when running PostCSS, Babel etc., so you can do `process.env.HUGO_FILE_TAILWIND_CONFIG_JS` to resolve the real filename.

But do note that `assets` is a composite/union filesystem, so if your config file is not meant to be overridden, name them something specific.

This commit also adds adds `workDir/node_modules` to `NODE_PATH` and `HUGO_WORKDIR` to the env when running the JS tools above.

Fixes #7644
Fixes #7656
Fixes #7675

commands/mod.go

@@ -1,4 +1,4 @@
-// Copyright 2019 The Hugo Authors. All rights reserved.
+// Copyright 2020 The Hugo Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -20,6 +20,8 @@ import (
 	"path/filepath"
 	"regexp"
 
+	"github.com/gohugoio/hugo/hugolib"
+
 	"github.com/gohugoio/hugo/modules"
 	"github.com/spf13/cobra"
 )
@@ -114,6 +116,8 @@ This is not needed if you only operate on modules inside /themes or if you have
 		RunE: nil,
 	}
 
+	cmd.AddCommand(newModNPMCmd(c))
+
 	cmd.AddCommand(
 		&cobra.Command{
 			Use:                "get",
@@ -272,6 +276,15 @@ func (c *modCmd) withModsClient(failOnMissingConfig bool, f func(*modules.Client
 	return f(com.hugo().ModulesClient)
 }
 
+func (c *modCmd) withHugo(f func(*hugolib.HugoSites) error) error {
+	com, err := c.initConfig(true)
+	if err != nil {
+		return err
+	}
+
+	return f(com.hugo())
+}
+
 func (c *modCmd) initConfig(failOnNoConfig bool) (*commandeer, error) {
 	com, err := initializeConfig(failOnNoConfig, false, &c.hugoBuilderCommon, c, nil)
 	if err != nil {

commands/mod_npm.go

@@ -0,0 +1,58 @@
+// Copyright 2020 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package commands
+
+import (
+	"github.com/gohugoio/hugo/hugolib"
+	"github.com/gohugoio/hugo/modules/npm"
+	"github.com/spf13/cobra"
+)
+
+func newModNPMCmd(c *modCmd) *cobra.Command {
+
+	cmd := &cobra.Command{
+		Use:   "npm",
+		Short: "Various npm helpers.",
+		Long:  `Various npm (Node package manager) helpers.`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			return c.withHugo(func(h *hugolib.HugoSites) error {
+				return nil
+			})
+		},
+	}
+
+	cmd.AddCommand(&cobra.Command{
+		Use:   "pack",
+		Short: "Experimental: Prepares and writes a composite package.json file for your project.",
+		Long: `Prepares and writes a composite package.json file for your project.
+
+On first run it creates a "package.hugo.json" in the project root if not alread there. This file will be used as a template file
+with the base dependency set. 
+
+This set will be merged with all "package.hugo.json" files found in the dependency tree, picking the version closest to the project.
+
+This command is marked as 'Experimental'. We think it's a great idea, so it's not likely to be
+removed from Hugo, but we need to test this out in "real life" to get a feel of it,
+so this may/will change in future versions of Hugo.
+`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+
+			return c.withHugo(func(h *hugolib.HugoSites) error {
+				return npm.Pack(h.BaseFs.SourceFs, h.BaseFs.Assets.Dirs)
+			})
+		},
+	})
+
+	return cmd
+}

common/hugo/hugo.go

@@ -17,8 +17,15 @@ import (
 	"fmt"
 	"html/template"
 	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/gohugoio/hugo/hugofs/files"
+
+	"github.com/spf13/afero"
 
 	"github.com/gohugoio/hugo/config"
+	"github.com/gohugoio/hugo/hugofs"
 )
 
 const (
@@ -73,8 +80,23 @@ func NewInfo(environment string) Info {
 	}
 }
 
-func GetExecEnviron(cfg config.Provider) []string {
+func GetExecEnviron(workDir string, cfg config.Provider, fs afero.Fs) []string {
 	env := os.Environ()
+	nodepath := filepath.Join(workDir, "node_modules")
+	if np := os.Getenv("NODE_PATH"); np != "" {
+		nodepath = workDir + string(os.PathListSeparator) + np
+	}
+	config.SetEnvVars(&env, "NODE_PATH", nodepath)
+	config.SetEnvVars(&env, "HUGO_WORKDIR", workDir)
 	config.SetEnvVars(&env, "HUGO_ENVIRONMENT", cfg.GetString("environment"))
+	fis, err := afero.ReadDir(fs, files.FolderJSConfig)
+	if err == nil {
+		for _, fi := range fis {
+			key := fmt.Sprintf("HUGO_FILE_%s", strings.ReplaceAll(strings.ToUpper(fi.Name()), ".", "_"))
+			value := fi.(hugofs.FileMetaInfo).Meta().Filename()
+			config.SetEnvVars(&env, key, value)
+		}
+	}
+
 	return env
 }

docs/content/en/hugo-pipes/babel.md

@@ -24,6 +24,30 @@ Hugo Pipe's Babel requires the `@babel/cli` and `@babel/core` JavaScript package
 If you are using the Hugo Snap package, Babel and plugin(s) need to be installed locally within your Hugo site directory, e.g., `npm install @babel/cli @babel/core --save-dev` without the `-g` flag.
 {{% /note %}}
 
+
+### Config
+
+{{< new-in "v0.75.0" >}}
+
+In Hugo `v0.75` we improved the way we resolve JS configuration and dependencies. One of them is that we now adds the main project's `node_modules` to `NODE_PATH` when running Babel and similar tools. There are some known [issues](https://github.com/babel/babel/issues/5618) with Babel in this area, so if you have a `babel.config.js` living in a Hugo Module (and not in the project itself), we recommend using `require` to load the presets/plugins, e.g.:
+
+
+```js
+module.exports = {
+        presets: [
+                [
+                        require('@babel/preset-env'),
+                        {
+                                useBuiltIns: 'entry',
+                                corejs: 3
+                        }
+                ]
+        ]
+};
+```
+
+
+
 ### Options
 
 config [string]

hugofs/files/classifier.go

@@ -26,6 +26,13 @@ import (
 	"github.com/spf13/afero"
 )
 
+const (
+	// The NPM package.json "template" file.
+	FilenamePackageHugoJSON = "package.hugo.json"
+	// The NPM package file.
+	FilenamePackageJSON = "package.json"
+)
+
 var (
 	// This should be the only list of valid extensions for content files.
 	contentFileExtensions = []string{
@@ -163,9 +170,12 @@ const (
 	ComponentFolderI18n       = "i18n"
 
 	FolderResources = "resources"
+	FolderJSConfig  = "_jsconfig" // Mounted below /assets with postcss.config.js etc.
 )
 
 var (
+	JsConfigFolderMountPrefix = filepath.Join(ComponentFolderAssets, FolderJSConfig)
+
 	ComponentFolders = []string{
 		ComponentFolderArchetypes,
 		ComponentFolderStatic,

hugofs/rootmapping_fs.go

@@ -42,9 +42,6 @@ func NewRootMappingFs(fs afero.Fs, rms ...RootMapping) (*RootMappingFs, error) {
 		(&rm).clean()
 
 		fromBase := files.ResolveComponentFolder(rm.From)
-		if fromBase == "" {
-			panic("unrecognised component folder in" + rm.From)
-		}
 
 		if len(rm.To) < 2 {
 			panic(fmt.Sprintf("invalid root mapping; from/to: %s/%s", rm.From, rm.To))

hugofs/walk_test.go

@@ -21,8 +21,6 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/gohugoio/hugo/common/hugo"
-
 	"github.com/pkg/errors"
 
 	"github.com/gohugoio/hugo/htesting"
@@ -129,12 +127,6 @@ func TestWalkSymbolicLink(t *testing.T) {
 	})
 
 	t.Run("BasePath Fs", func(t *testing.T) {
-		if hugo.GoMinorVersion() < 12 {
-			// https://github.com/golang/go/issues/30520
-			// This is fixed in Go 1.13 and in the latest Go 1.12
-			t.Skip("skip this for Go <= 1.11 due to a bug in Go's stdlib")
-
-		}
 		c := qt.New(t)
 
 		docsFs := afero.NewBasePathFs(fs, docsDir)

hugolib/filesystems/basefs.go

@@ -49,6 +49,9 @@ type BaseFs struct {
 	// SourceFilesystems contains the different source file systems.
 	*SourceFilesystems
 
+	// The project source.
+	SourceFs afero.Fs
+
 	// The filesystem used to publish the rendered site.
 	// This usually maps to /my-project/public.
 	PublishFs afero.Fs
@@ -100,6 +103,23 @@ func (b *BaseFs) RelContentDir(filename string) string {
 	return filename
 }
 
+// ResolveJSConfigFile resolves the JS-related config file to a absolute
+// filename. One example of such would be postcss.config.js.
+func (fs *BaseFs) ResolveJSConfigFile(name string) string {
+	// First look in assets/_jsconfig
+	fi, err := fs.Assets.Fs.Stat(filepath.Join(files.FolderJSConfig, name))
+	if err == nil {
+		return fi.(hugofs.FileMetaInfo).Meta().Filename()
+	}
+	// Fall back to the work dir.
+	fi, err = fs.Work.Stat(name)
+	if err == nil {
+		return fi.(hugofs.FileMetaInfo).Meta().Filename()
+	}
+
+	return ""
+}
+
 // SourceFilesystems contains the different source file systems. These can be
 // composite file systems (theme and project etc.), and they have all root
 // set to the source type the provides: data, i18n, static, layouts.
@@ -346,8 +366,10 @@ func NewBase(p *paths.Paths, logger *loggers.Logger, options ...func(*BaseFs) er
 	}
 
 	publishFs := hugofs.NewBaseFileDecorator(afero.NewBasePathFs(fs.Destination, p.AbsPublishDir))
+	sourceFs := hugofs.NewBaseFileDecorator(afero.NewBasePathFs(fs.Source, p.WorkingDir))
 
 	b := &BaseFs{
+		SourceFs:  sourceFs,
 		PublishFs: publishFs,
 	}
 
@@ -696,11 +718,16 @@ type filesystemsCollector struct {
 
 func (c *filesystemsCollector) addDirs(rfs *hugofs.RootMappingFs) {
 	for _, componentFolder := range files.ComponentFolders {
-		dirs, err := rfs.Dirs(componentFolder)
+		c.addDir(rfs, componentFolder)
+	}
 
-		if err == nil {
-			c.overlayDirs[componentFolder] = append(c.overlayDirs[componentFolder], dirs...)
-		}
+}
+
+func (c *filesystemsCollector) addDir(rfs *hugofs.RootMappingFs, componentFolder string) {
+	dirs, err := rfs.Dirs(componentFolder)
+
+	if err == nil {
+		c.overlayDirs[componentFolder] = append(c.overlayDirs[componentFolder], dirs...)
 	}
 }