Add js.Batch

Fixes #12626
Closes #7499
Closes #9978
Closes #12879
Closes #13113
Fixes #13116

tpl/js/js.go

@@ -1,4 +1,4 @@
-// Copyright 2020 The Hugo Authors. All rights reserved.
+// Copyright 2024 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.
@@ -17,29 +17,47 @@ package js
 import (
 	"errors"
 
+	"github.com/gohugoio/hugo/common/maps"
 	"github.com/gohugoio/hugo/deps"
+	"github.com/gohugoio/hugo/internal/js/esbuild"
 	"github.com/gohugoio/hugo/resources"
 	"github.com/gohugoio/hugo/resources/resource"
+	"github.com/gohugoio/hugo/resources/resource_factories/create"
 	"github.com/gohugoio/hugo/resources/resource_transformers/babel"
-	"github.com/gohugoio/hugo/resources/resource_transformers/js"
+	jstransform "github.com/gohugoio/hugo/resources/resource_transformers/js"
 	"github.com/gohugoio/hugo/tpl/internal/resourcehelpers"
 )
 
 // New returns a new instance of the js-namespaced template functions.
-func New(deps *deps.Deps) *Namespace {
-	if deps.ResourceSpec == nil {
-		return &Namespace{}
+func New(d *deps.Deps) (*Namespace, error) {
+	if d.ResourceSpec == nil {
+		return &Namespace{}, nil
 	}
+
+	batcherClient, err := esbuild.NewBatcherClient(d)
+	if err != nil {
+		return nil, err
+	}
+
 	return &Namespace{
-		client:      js.New(deps.BaseFs.Assets, deps.ResourceSpec),
-		babelClient: babel.New(deps.ResourceSpec),
-	}
+		d:                 d,
+		jsTransformClient: jstransform.New(d.BaseFs.Assets, d.ResourceSpec),
+		jsBatcherClient:   batcherClient,
+		jsBatcherStore:    maps.NewCache[string, esbuild.Batcher](),
+		createClient:      create.New(d.ResourceSpec),
+		babelClient:       babel.New(d.ResourceSpec),
+	}, nil
 }
 
 // Namespace provides template functions for the "js" namespace.
 type Namespace struct {
-	client      *js.Client
-	babelClient *babel.Client
+	d *deps.Deps
+
+	jsTransformClient *jstransform.Client
+	createClient      *create.Client
+	babelClient       *babel.Client
+	jsBatcherClient   *esbuild.BatcherClient
+	jsBatcherStore    *maps.Cache[string, esbuild.Batcher]
 }
 
 // Build processes the given Resource with ESBuild.
@@ -65,7 +83,24 @@ func (ns *Namespace) Build(args ...any) (resource.Resource, error) {
 		m = map[string]any{"targetPath": targetPath}
 	}
 
-	return ns.client.Process(r, m)
+	return ns.jsTransformClient.Process(r, m)
+}
+
+// Batch creates a new Batcher with the given ID.
+// Repeated calls with the same ID will return the same Batcher.
+// The ID will be used to name the root directory of the batch.
+// Forward slashes in the ID is allowed.
+func (ns *Namespace) Batch(id string) (esbuild.Batcher, error) {
+	if err := esbuild.ValidateBatchID(id, true); err != nil {
+		return nil, err
+	}
+	b, err := ns.jsBatcherStore.GetOrCreate(id, func() (esbuild.Batcher, error) {
+		return ns.jsBatcherClient.New(id)
+	})
+	if err != nil {
+		return nil, err
+	}
+	return b, nil
 }
 
 // Babel processes the given Resource with Babel.