pipes: Add external source map support to js.Build and Babel

Fixes #8132

6 files changed, 138 insertions, 4 deletions

diff --git a/hugolib/js_test.go b/hugolib/js_test.go
index a1b74a871..145a057c1 100644
--- a/hugolib/js_test.go
+++ b/hugolib/js_test.go
@@ -109,14 +109,16 @@ document.body.textContent = greeter(user);`
 JS:  {{ template "print" $js }}
 {{ $jsx := resources.Get "js/myjsx.jsx" | js.Build $options }}
 JSX: {{ template "print" $jsx }}
-{{ $ts := resources.Get "js/myts.ts" | js.Build }}
+{{ $ts := resources.Get "js/myts.ts" | js.Build (dict "sourcemap" "inline")}}
 TS: {{ template "print" $ts }}
-
+{{ $ts2 := resources.Get "js/myts.ts" | js.Build (dict "sourcemap" "external" "TargetPath" "js/myts2.js")}}
+TS2: {{ template "print" $ts2 }}
 {{ define "print" }}RelPermalink: {{.RelPermalink}}|MIME: {{ .MediaType }}|Content: {{ .Content | safeJS }}{{ end }}
 
 `)
 
 	jsDir := filepath.Join(workDir, "assets", "js")
+	fmt.Println(workDir)
 	b.Assert(os.MkdirAll(jsDir, 0777), qt.IsNil)
 	b.Assert(os.Chdir(workDir), qt.IsNil)
 	b.WithSourceFile("package.json", packageJSON)
@@ -133,6 +135,8 @@ TS: {{ template "print" $ts }}
 
 	b.Build(BuildCfg{})
 
+	b.AssertFileContent("public/js/myts.js", `//# sourceMappingURL=data:application/json;base64,ewogICJ2ZXJz`)
+	b.AssertFileContent("public/js/myts2.js.map", `"version": 3,`)
 	b.AssertFileContent("public/index.html", `
 console.log("included");
 if (hasSpace.test(string))
diff --git a/hugolib/resource_chain_babel_test.go b/hugolib/resource_chain_babel_test.go
index d5e99cd17..77c81f9ca 100644
--- a/hugolib/resource_chain_babel_test.go
+++ b/hugolib/resource_chain_babel_test.go
@@ -80,6 +80,15 @@ class Car {
 }
 `
 
+	js2 := `
+/* A Car2 */
+class Car2 {
+  constructor(brand) {
+    this.carname = brand;
+  }
+}
+`
+
 	workDir, clean, err := htesting.CreateTempDir(hugofs.Os, "hugo-test-babel")
 	c.Assert(err, qt.IsNil)
 	defer clean()
@@ -103,11 +112,18 @@ class Car {
 {{ $transpiled := resources.Get "js/main.js" | babel -}}
 Transpiled: {{ $transpiled.Content | safeJS }}
 
+{{ $transpiled := resources.Get "js/main2.js" | babel (dict "sourceMap" "inline") -}}
+Transpiled2: {{ $transpiled.Content | safeJS }}
+
+{{ $transpiled := resources.Get "js/main2.js" | babel (dict "sourceMap" "external") -}}
+Transpiled3: {{ $transpiled.Permalink }}
+
 `)
 
 	jsDir := filepath.Join(workDir, "assets", "js")
 	b.Assert(os.MkdirAll(jsDir, 0777), qt.IsNil)
 	b.WithSourceFile("assets/js/main.js", js)
+	b.WithSourceFile("assets/js/main2.js", js2)
 	b.WithSourceFile("package.json", packageJSON)
 	b.WithSourceFile("babel.config.js", babelConfig)
 
@@ -129,4 +145,21 @@ var Car = function Car(brand) {
  this.carname = brand;
 };
 `)
+	b.AssertFileContent("public/index.html", `
+var Car2 = function Car2(brand) {
+ _classCallCheck(this, Car2);
+
+ this.carname = brand;
+};
+`)
+	b.AssertFileContent("public/js/main2.js", `
+var Car2 = function Car2(brand) {
+ _classCallCheck(this, Car2);
+
+ this.carname = brand;
+};
+`)
+	b.AssertFileContent("public/js/main2.js.map", `{"version":3,`)
+	b.AssertFileContent("public/index.html", `
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozL`)
 }
diff --git a/resources/resource_transformers/babel/babel.go b/resources/resource_transformers/babel/babel.go
index 204153705..e291b210b 100644
--- a/resources/resource_transformers/babel/babel.go
+++ b/resources/resource_transformers/babel/babel.go
@@ -16,7 +16,11 @@ package babel
 import (
 	"bytes"
 	"io"
+	"io/ioutil"
+	"os"
+	"path"
 	"path/filepath"
+	"regexp"
 	"strconv"
 
 	"github.com/cli/safeexec"
@@ -43,8 +47,10 @@ type Options struct {
 	Compact    *bool
 	Verbose    bool
 	NoBabelrc  bool
+	SourceMap  string
 }
 
+// DecodeOptions decodes options to and generates command flags
 func DecodeOptions(m map[string]interface{}) (opts Options, err error) {
 	if m == nil {
 		return
@@ -56,6 +62,14 @@ func DecodeOptions(m map[string]interface{}) (opts Options, err error) {
 func (opts Options) toArgs() []string {
 	var args []string
 
+	// external is not a known constant on the babel command line
+	// .sourceMaps must be a boolean, "inline", "both", or undefined
+	switch opts.SourceMap {
+	case "external":
+		args = append(args, "--source-maps")
+	case "inline":
+		args = append(args, "--source-maps=inline")
+	}
 	if opts.Minified {
 		args = append(args, "--minified")
 	}
@@ -141,6 +155,8 @@ func (t *babelTransformation) Transform(ctx *resources.ResourceTransformationCtx
 		}
 	}
 
+	ctx.ReplaceOutPathExtension(".js")
+
 	var cmdArgs []string
 
 	if configFile != "" {
@@ -153,13 +169,24 @@ func (t *babelTransformation) Transform(ctx *resources.ResourceTransformationCtx
 	}
 	cmdArgs = append(cmdArgs, "--filename="+ctx.SourcePath)
 
+	// Create compile into a real temp file:
+	// 1. separate stdout/stderr messages from babel (https://github.com/gohugoio/hugo/issues/8136)
+	// 2. allow generation and retrieval of external source map.
+	compileOutput, err := ioutil.TempFile("", "compileOut-*.js")
+	if err != nil {
+		return err
+	}
+
+	cmdArgs = append(cmdArgs, "--out-file="+compileOutput.Name())
+	defer os.Remove(compileOutput.Name())
+
 	cmd, err := hexec.SafeCommand(binary, cmdArgs...)
 	if err != nil {
 		return err
 	}
 
-	cmd.Stdout = ctx.To
 	cmd.Stderr = io.MultiWriter(infoW, &errBuf)
+	cmd.Stdout = cmd.Stderr
 	cmd.Env = hugo.GetExecEnviron(t.rs.WorkingDir, t.rs.Cfg, t.rs.BaseFs.Assets.Fs)
 
 	stdin, err := cmd.StdinPipe()
@@ -177,6 +204,28 @@ func (t *babelTransformation) Transform(ctx *resources.ResourceTransformationCtx
 		return errors.Wrap(err, errBuf.String())
 	}
 
+	content, err := ioutil.ReadAll(compileOutput)
+	if err != nil {
+		return err
+	}
+
+	mapFile := compileOutput.Name() + ".map"
+	if _, err := os.Stat(mapFile); err == nil {
+		defer os.Remove(mapFile)
+		sourceMap, err := ioutil.ReadFile(mapFile)
+		if err != nil {
+			return err
+		}
+		if err = ctx.PublishSourceMap(string(sourceMap)); err != nil {
+			return err
+		}
+		targetPath := path.Base(ctx.OutPath) + ".map"
+		re := regexp.MustCompile(`//# sourceMappingURL=.*\n?`)
+		content = []byte(re.ReplaceAllString(string(content), "//# sourceMappingURL="+targetPath+"\n"))
+	}
+
+	ctx.To.Write(content)
+
 	return nil
 }
 
diff --git a/resources/resource_transformers/js/build.go b/resources/resource_transformers/js/build.go
index 5ff21cf02..0d70bdc33 100644
--- a/resources/resource_transformers/js/build.go
+++ b/resources/resource_transformers/js/build.go
@@ -18,6 +18,8 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"path"
+	"regexp"
 	"strings"
 
 	"github.com/spf13/afero"
@@ -92,6 +94,14 @@ func (t *buildTransformation) Transform(ctx *resources.ResourceTransformationCtx
 		return err
 	}
 
+	if buildOptions.Sourcemap == api.SourceMapExternal && buildOptions.Outdir == "" {
+		buildOptions.Outdir, err = ioutil.TempDir(os.TempDir(), "compileOutput")
+		if err != nil {
+			return err
+		}
+		defer os.Remove(buildOptions.Outdir)
+	}
+
 	result := api.Build(buildOptions)
 
 	if len(result.Errors) > 0 {
@@ -145,7 +155,25 @@ func (t *buildTransformation) Transform(ctx *resources.ResourceTransformationCtx
 		return errors[0]
 	}
 
-	ctx.To.Write(result.OutputFiles[0].Contents)
+	if buildOptions.Sourcemap == api.SourceMapExternal {
+		content := string(result.OutputFiles[1].Contents)
+		symPath := path.Base(ctx.OutPath) + ".map"
+		re := regexp.MustCompile(`//# sourceMappingURL=.*\n?`)
+		content = re.ReplaceAllString(content, "//# sourceMappingURL="+symPath+"\n")
+
+		if err = ctx.PublishSourceMap(string(result.OutputFiles[0].Contents)); err != nil {
+			return err
+		}
+		_, err := ctx.To.Write([]byte(content))
+		if err != nil {
+			return err
+		}
+	} else {
+		_, err := ctx.To.Write(result.OutputFiles[0].Contents)
+		if err != nil {
+			return err
+		}
+	}
 	return nil
 }
 
diff --git a/resources/resource_transformers/js/options.go b/resources/resource_transformers/js/options.go
index 75daa0cad..5236fe126 100644
--- a/resources/resource_transformers/js/options.go
+++ b/resources/resource_transformers/js/options.go
@@ -338,6 +338,8 @@ func toBuildOptions(opts Options) (buildOptions api.BuildOptions, err error) {
 	switch opts.SourceMap {
 	case "inline":
 		sourceMap = api.SourceMapInline
+	case "external":
+		sourceMap = api.SourceMapExternal
 	case "":
 		sourceMap = api.SourceMapNone
 	default:
diff --git a/resources/resource_transformers/js/options_test.go b/resources/resource_transformers/js/options_test.go
index f07ccc26b..f425c3e75 100644
--- a/resources/resource_transformers/js/options_test.go
+++ b/resources/resource_transformers/js/options_test.go
@@ -109,4 +109,22 @@ func TestToBuildOptions(t *testing.T) {
 			Loader: api.LoaderJS,
 		},
 	})
+
+	opts, err = toBuildOptions(Options{
+		Target: "es2018", Format: "cjs", Minify: true, mediaType: media.JavascriptType,
+		SourceMap: "external",
+	})
+	c.Assert(err, qt.IsNil)
+	c.Assert(opts, qt.DeepEquals, api.BuildOptions{
+		Bundle:            true,
+		Target:            api.ES2018,
+		Format:            api.FormatCommonJS,
+		MinifyIdentifiers: true,
+		MinifySyntax:      true,
+		MinifyWhitespace:  true,
+		Sourcemap:         api.SourceMapExternal,
+		Stdin: &api.StdinOptions{
+			Loader: api.LoaderJS,
+		},
+	})
 }