Add js.Build asset bundling

Fixes #7321

3 files changed, 127 insertions, 0 deletions

diff --git a/tpl/js/init.go b/tpl/js/init.go
new file mode 100644
index 000000000..0af10bb10
--- /dev/null
+++ b/tpl/js/init.go
@@ -0,0 +1,36 @@
+// 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 js
+
+import (
+	"github.com/gohugoio/hugo/deps"
+	"github.com/gohugoio/hugo/tpl/internal"
+)
+
+const name = "js"
+
+func init() {
+	f := func(d *deps.Deps) *internal.TemplateFuncsNamespace {
+		ctx := New(d)
+
+		ns := &internal.TemplateFuncsNamespace{
+			Name:    name,
+			Context: func(args ...interface{}) interface{} { return ctx },
+		}
+
+		return ns
+	}
+
+	internal.AddTemplateFuncsNamespace(f)
+}
diff --git a/tpl/js/js.go b/tpl/js/js.go
new file mode 100644
index 000000000..d8ba35a76
--- /dev/null
+++ b/tpl/js/js.go
@@ -0,0 +1,90 @@
+// 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 js provides functions for building JavaScript resources
+package js
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/gohugoio/hugo/common/maps"
+	"github.com/gohugoio/hugo/deps"
+	"github.com/gohugoio/hugo/resources"
+	"github.com/gohugoio/hugo/resources/resource"
+	"github.com/gohugoio/hugo/resources/resource_transformers/js"
+	_errors "github.com/pkg/errors"
+)
+
+// New returns a new instance of the js-namespaced template functions.
+func New(deps *deps.Deps) *Namespace {
+	return &Namespace{
+		client: js.New(deps.BaseFs.Assets, deps.ResourceSpec),
+	}
+}
+
+// Namespace provides template functions for the "js" namespace.
+type Namespace struct {
+	deps   *deps.Deps
+	client *js.Client
+}
+
+// Build processes the given Resource with ESBuild.
+func (ns *Namespace) Build(args ...interface{}) (resource.Resource, error) {
+	r, m, err := ns.resolveArgs(args)
+	if err != nil {
+		return nil, err
+	}
+	var options js.Options
+	if m != nil {
+		options, err = js.DecodeOptions(m)
+
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return ns.client.Process(r, options)
+
+}
+
+// This roundabout way of doing it is needed to get both pipeline behaviour and options as arguments.
+// This is a copy of tpl/resources/resolveArgs
+func (ns *Namespace) resolveArgs(args []interface{}) (resources.ResourceTransformer, map[string]interface{}, error) {
+	if len(args) == 0 {
+		return nil, nil, errors.New("no Resource provided in transformation")
+	}
+
+	if len(args) == 1 {
+		r, ok := args[0].(resources.ResourceTransformer)
+		if !ok {
+			return nil, nil, fmt.Errorf("type %T not supported in Resource transformations", args[0])
+		}
+		return r, nil, nil
+	}
+
+	r, ok := args[1].(resources.ResourceTransformer)
+	if !ok {
+		if _, ok := args[1].(map[string]interface{}); !ok {
+			return nil, nil, fmt.Errorf("no Resource provided in transformation")
+		}
+		return nil, nil, fmt.Errorf("type %T not supported in Resource transformations", args[0])
+	}
+
+	m, err := maps.ToStringMapE(args[0])
+	if err != nil {
+		return nil, nil, _errors.Wrap(err, "invalid options type")
+	}
+
+	return r, m, nil
+}
diff --git a/tpl/tplimpl/template_funcs.go b/tpl/tplimpl/template_funcs.go
index 9141de3f1..a688abb77 100644
--- a/tpl/tplimpl/template_funcs.go
+++ b/tpl/tplimpl/template_funcs.go
@@ -42,6 +42,7 @@ import (
 	_ "github.com/gohugoio/hugo/tpl/hugo"
 	_ "github.com/gohugoio/hugo/tpl/images"
 	_ "github.com/gohugoio/hugo/tpl/inflect"
+	_ "github.com/gohugoio/hugo/tpl/js"
 	_ "github.com/gohugoio/hugo/tpl/lang"
 	_ "github.com/gohugoio/hugo/tpl/math"
 	_ "github.com/gohugoio/hugo/tpl/openapi/openapi3"