add custom js functions for templates

.gitignore

@@ -3,3 +3,4 @@
 /examples/react-app-generator/generated-blog-app/node_modules/
 /examples/react-app-generator/generated-app/node_modules/
 /examples/react-app-generator/generated-app/
+/examples/custom-js-functions/generated-app/

examples/custom-js-functions/blog-example.masonry

@@ -0,0 +1,31 @@
+entity User {
+  name: string required
+  email: string required unique
+  password: string required
+  bio: text
+  createdAt: timestamp
+  updatedAt: timestamp
+}
+
+entity Post {
+  title: string required
+  slug: string required unique
+  content: text required
+  published: boolean
+  authorId: uuid required relates to User as one via "authorId"
+  createdAt: timestamp
+  updatedAt: timestamp
+}
+
+entity Comment {
+  content: text required
+  authorId: uuid required relates to User as one via "authorId"
+  postId: uuid required relates to Post as one via "postId"
+  createdAt: timestamp
+}
+
+server BlogAPI {
+  host "localhost"
+  port 3000
+  database_url env "DATABASE_URL" default "postgres://localhost/blog"
+}

examples/custom-js-functions/readme.md

@@ -0,0 +1,68 @@
+# Custom JavaScript Functions Example
+
+This example demonstrates how to use custom JavaScript functions in Masonry templates using the Otto JavaScript interpreter. You can define custom template functions directly in your `manifest.yaml` files, allowing for dynamic code generation that can be customized without recompiling the CLI tool.
+
+## Overview
+
+The custom JavaScript functions feature allows you to:
+- Define JavaScript functions in your `manifest.yaml` files
+- Use these functions in your templates just like built-in template functions
+- Perform complex string manipulations, data transformations, and logic
+- Extend template functionality dynamically
+
+## How It Works
+
+1. **Define Functions**: Add a `functions` section to your `manifest.yaml` file
+2. **JavaScript Code**: Each function is written in JavaScript and must define a `main()` function
+3. **Template Usage**: Use the custom functions in your templates like any other template function
+4. **Otto Execution**: The Otto JavaScript interpreter executes your functions at template generation time
+
+## Function Structure
+
+Each custom function must follow this structure:
+
+```javascript
+function main() {
+    // Your custom logic here
+    // Access arguments via the global 'args' array: args[0], args[1], etc.
+    // Or via individual variables: arg0, arg1, etc.
+    
+    return "your result";
+}
+```
+
+## Example Files
+
+- `blog-example.masonry` - Sample Masonry file defining a blog application
+- `templates/manifest.yaml` - Manifest with custom JavaScript functions
+- `templates/model.tmpl` - Template using the custom functions
+- `templates/controller.tmpl` - Another template demonstrating function usage
+
+## Running the Example
+
+```bash
+# From the masonry project root
+./masonry.exe generate templates examples/custom-js-functions/blog-example.masonry examples/custom-js-functions/templates manifest.yaml
+```
+
+## Custom Functions in This Example
+
+### `generateSlug`
+Converts a title to a URL-friendly slug:
+- Input: "My Blog Post Title"
+- Output: "my-blog-post-title"
+
+### `pluralize`
+Converts singular words to plural:
+- Input: "post"
+- Output: "posts"
+
+### `generateValidation`
+Creates validation rules based on field type:
+- Input: field type
+- Output: appropriate validation code
+
+### `formatComment`
+Generates formatted code comments:
+- Input: text
+- Output: properly formatted comment block

examples/custom-js-functions/templates/controller.tmpl

@@ -0,0 +1,97 @@
+package controllers
+
+import (
+	"encoding/json"
+	"net/http"
+	"strconv"
+
+	"github.com/gorilla/mux"
+	"your-app/models"
+)
+
+{{formatComment (printf "Controller for %s entity\nGenerated with custom JavaScript template functions" .Entity.Name)}}
+type {{.Entity.Name | title}}Controller struct {
+	// Add your dependencies here (e.g., database, services)
+}
+
+{{formatComment "Create a new controller instance"}}
+func New{{.Entity.Name | title}}Controller() *{{.Entity.Name | title}}Controller {
+	return &{{.Entity.Name | title}}Controller{}
+}
+
+{{formatComment "GET /{{pluralize (.Entity.Name | lower)}}"}}
+func (c *{{.Entity.Name | title}}Controller) List{{pluralize (.Entity.Name | title)}}(w http.ResponseWriter, r *http.Request) {
+	// Implementation for listing {{pluralize (.Entity.Name | lower)}}
+	w.Header().Set("Content-Type", "application/json")
+
+	// Example response
+	{{pluralize (.Entity.Name | lower)}} := []models.{{.Entity.Name | title}}{}
+	json.NewEncoder(w).Encode({{pluralize (.Entity.Name | lower)}})
+}
+
+{{formatComment "GET /{{pluralize (.Entity.Name | lower)}}/:id"}}
+func (c *{{.Entity.Name | title}}Controller) Get{{.Entity.Name | title}}(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	id := vars["id"]
+
+	// Convert id and fetch {{.Entity.Name | lower}}
+	_ = id // TODO: implement fetch logic
+
+	w.Header().Set("Content-Type", "application/json")
+	// json.NewEncoder(w).Encode({{.Entity.Name | lower}})
+}
+
+{{formatComment "POST /{{pluralize (.Entity.Name | lower)}}"}}
+func (c *{{.Entity.Name | title}}Controller) Create{{.Entity.Name | title}}(w http.ResponseWriter, r *http.Request) {
+	var {{.Entity.Name | lower}} models.{{.Entity.Name | title}}
+
+	if err := json.NewDecoder(r.Body).Decode(&{{.Entity.Name | lower}}); err != nil {
+		http.Error(w, "Invalid JSON", http.StatusBadRequest)
+		return
+	}
+
+	if err := {{.Entity.Name | lower}}.Validate(); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	// TODO: Save to database
+
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusCreated)
+	json.NewEncoder(w).Encode({{.Entity.Name | lower}})
+}
+
+{{formatComment "PUT /{{pluralize (.Entity.Name | lower)}}/:id"}}
+func (c *{{.Entity.Name | title}}Controller) Update{{.Entity.Name | title}}(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	id := vars["id"]
+
+	var {{.Entity.Name | lower}} models.{{.Entity.Name | title}}
+	if err := json.NewDecoder(r.Body).Decode(&{{.Entity.Name | lower}}); err != nil {
+		http.Error(w, "Invalid JSON", http.StatusBadRequest)
+		return
+	}
+
+	if err := {{.Entity.Name | lower}}.Validate(); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	// TODO: Update in database using id
+	_ = id
+
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode({{.Entity.Name | lower}})
+}
+
+{{formatComment "DELETE /{{pluralize (.Entity.Name | lower)}}/:id"}}
+func (c *{{.Entity.Name | title}}Controller) Delete{{.Entity.Name | title}}(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	id := vars["id"]
+
+	// TODO: Delete from database using id
+	_ = id
+
+	w.WriteHeader(http.StatusNoContent)
+}

examples/custom-js-functions/templates/manifest.yaml

@@ -0,0 +1,104 @@
+name: "Blog Generator with Custom JS Functions"
+description: "Demonstrates custom JavaScript template functions using Otto interpreter"
+
+# Custom JavaScript functions that can be used in templates
+functions:
+  # Convert a string to a URL-friendly slug
+  generateSlug: |
+    function main() {
+      var input = args[0] || "";
+      return input
+        .toLowerCase()
+        .replace(/[^a-z0-9]+/g, '-')
+        .replace(/^-+|-+$/g, '');
+    }
+
+  # Convert singular words to plural (simple English rules) - ES5 compatible
+  pluralize: |
+    function main() {
+      var word = args[0] || "";
+      if (word.slice(-1) === 'y') {
+        return word.slice(0, -1) + 'ies';
+      } else if (word.slice(-1) === 's' || word.slice(-2) === 'sh' || word.slice(-2) === 'ch' || word.slice(-1) === 'x' || word.slice(-1) === 'z') {
+        return word + 'es';
+      } else {
+        return word + 's';
+      }
+    }
+
+  # Generate validation rules based on field type
+  generateValidation: |
+    function main() {
+      var fieldType = args[0] || "";
+      var fieldName = args[1] || "field";
+      
+      switch (fieldType) {
+        case 'string':
+          return 'if len(' + fieldName + ') == 0 { return errors.New("' + fieldName + ' is required") }';
+        case 'uuid':
+          return 'if _, err := uuid.Parse(' + fieldName + '); err != nil { return errors.New("invalid UUID format") }';
+        case 'boolean':
+          return '// Boolean validation not required';
+        case 'timestamp':
+          return 'if ' + fieldName + '.IsZero() { return errors.New("' + fieldName + ' is required") }';
+        default:
+          return '// No validation rules for type: ' + fieldType;
+      }
+    }
+
+  # Format a comment block
+  formatComment: |
+    function main() {
+      var text = args[0] || "";
+      var lines = text.split('\n');
+      var result = '// ' + lines.join('\n// ');
+      return result;
+    }
+
+  # Generate database field mapping
+  dbFieldMapping: |
+    function main() {
+      var fieldName = args[0] || "";
+      var fieldType = args[1] || "string";
+      
+      var dbType;
+      switch (fieldType) {
+        case 'string':
+          dbType = 'VARCHAR(255)';
+          break;
+        case 'text':
+          dbType = 'TEXT';
+          break;
+        case 'uuid':
+          dbType = 'UUID';
+          break;
+        case 'boolean':
+          dbType = 'BOOLEAN';
+          break;
+        case 'timestamp':
+          dbType = 'TIMESTAMP';
+          break;
+        default:
+          dbType = 'VARCHAR(255)';
+      }
+      
+      return '`db:"' + fieldName.toLowerCase() + '" json:"' + fieldName + '"`';
+    }
+
+outputs:
+  # Generate Go models for each entity using custom functions
+  - path: "models/{{.Entity.Name | lower}}.go"
+    template: "model"
+    iterator: "entities"
+    item_context: "Entity"
+
+  # Generate controllers for each entity
+  - path: "controllers/{{.Entity.Name | lower}}_controller.go"
+    template: "controller"
+    iterator: "entities"
+    item_context: "Entity"
+
+  # Generate a single router file
+  - path: "router.go"
+    template: "router"
+    condition: "has_entities"

examples/custom-js-functions/templates/model.tmpl

@@ -0,0 +1,44 @@
+package models
+
+import (
+	"errors"
+	"time"
+	"github.com/google/uuid"
+)
+
+{{formatComment (printf "Model for %s entity\nGenerated with custom JavaScript functions" .Entity.Name)}}
+type {{.Entity.Name | title}} struct {
+{{- range .Entity.Fields}}
+	{{.Name | title}} {{goType .Type}} {{dbFieldMapping .Name .Type}}
+{{- end}}
+}
+
+{{formatComment "Table name for GORM"}}
+func ({{.Entity.Name | title}}) TableName() string {
+	return "{{pluralize (.Entity.Name | lower)}}"
+}
+
+{{formatComment "Validation function using custom JavaScript validation rules"}}
+func (m *{{.Entity.Name | title}}) Validate() error {
+{{- range .Entity.Fields}}
+	{{- if .Required}}
+	{{generateValidation .Type .Name}}
+	{{- end}}
+{{- end}}
+	return nil
+}
+
+{{formatComment "Create a new instance with validation"}}
+func New{{.Entity.Name | title}}({{range $i, $field := .Entity.Fields}}{{if $i}}, {{end}}{{$field.Name | lower}} {{goType $field.Type}}{{end}}) (*{{.Entity.Name | title}}, error) {
+	model := &{{.Entity.Name | title}}{
+{{- range .Entity.Fields}}
+		{{.Name | title}}: {{.Name | lower}},
+{{- end}}
+	}
+
+	if err := model.Validate(); err != nil {
+		return nil, err
+	}
+
+	return model, nil
+}

examples/custom-js-functions/templates/router.tmpl

@@ -0,0 +1,28 @@
+package main
+
+import (
+	"net/http"
+
+	"github.com/gorilla/mux"
+	"your-app/controllers"
+)
+
+{{formatComment "Router setup with all entity routes\nGenerated using custom JavaScript template functions"}}
+func SetupRouter() *mux.Router {
+	router := mux.NewRouter()
+
+	{{range $entity := .AST.Definitions}}
+	{{- if $entity.Entity}}
+	{{formatComment (printf "Routes for %s entity" $entity.Entity.Name)}}
+	{{$entity.Entity.Name | lower}}Controller := controllers.New{{$entity.Entity.Name | title}}Controller()
+	router.HandleFunc("/{{pluralize ($entity.Entity.Name | lower)}}", {{$entity.Entity.Name | lower}}Controller.List{{pluralize ($entity.Entity.Name | title)}}).Methods("GET")
+	router.HandleFunc("/{{pluralize ($entity.Entity.Name | lower)}}/:id", {{$entity.Entity.Name | lower}}Controller.Get{{$entity.Entity.Name | title}}).Methods("GET")
+	router.HandleFunc("/{{pluralize ($entity.Entity.Name | lower)}}", {{$entity.Entity.Name | lower}}Controller.Create{{$entity.Entity.Name | title}}).Methods("POST")
+	router.HandleFunc("/{{pluralize ($entity.Entity.Name | lower)}}/:id", {{$entity.Entity.Name | lower}}Controller.Update{{$entity.Entity.Name | title}}).Methods("PUT")
+	router.HandleFunc("/{{pluralize ($entity.Entity.Name | lower)}}/:id", {{$entity.Entity.Name | lower}}Controller.Delete{{$entity.Entity.Name | title}}).Methods("DELETE")
+
+	{{end}}
+	{{- end}}
+
+	return router
+}

go.mod

@@ -4,13 +4,15 @@ go 1.23
 
 require (
 	github.com/alecthomas/participle/v2 v2.1.4
+	github.com/robertkrimen/otto v0.5.1
 	github.com/urfave/cli/v2 v2.27.5
 	golang.org/x/text v0.22.0
+	gopkg.in/yaml.v3 v3.0.1
 )
 
 require (
 	github.com/cpuguy83/go-md2man/v2 v2.0.5 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
 	github.com/xrash/smetrics v0.0.0-20240521201337-686a1a2994c1 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
+	gopkg.in/sourcemap.v1 v1.0.5 // indirect
 )

go.sum

@@ -6,16 +6,27 @@ github.com/alecthomas/repr v0.4.0 h1:GhI2A8MACjfegCPVq9f1FLvIBS+DrQ2KQBFZP1iFzXc
 github.com/alecthomas/repr v0.4.0/go.mod h1:Fr0507jx4eOXV7AlPV6AVZLYrLIuIeSOWtW57eE/O/4=
 github.com/cpuguy83/go-md2man/v2 v2.0.5 h1:ZtcqGrnekaHpVLArFSe4HK5DoKx1T0rq2DwVB0alcyc=
 github.com/cpuguy83/go-md2man/v2 v2.0.5/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/hexops/gotextdiff v1.0.3 h1:gitA9+qJrrTCsiCl7+kh75nPqQt1cx4ZkudSTLoUqJM=
 github.com/hexops/gotextdiff v1.0.3/go.mod h1:pSWU5MAI3yDq+fZBTazCSJysOMbxWL1BSow5/V2vxeg=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/robertkrimen/otto v0.5.1 h1:avDI4ToRk8k1hppLdYFTuuzND41n37vPGJU7547dGf0=
+github.com/robertkrimen/otto v0.5.1/go.mod h1:bS433I4Q9p+E5pZLu7r17vP6FkE6/wLxBdmKjoqJXF8=
 github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf35Ld67mk=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
+github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
+github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/urfave/cli/v2 v2.27.5 h1:WoHEJLdsXr6dDWoJgMq/CboDmyY/8HMMH1fTECbih+w=
 github.com/urfave/cli/v2 v2.27.5/go.mod h1:3Sevf16NykTbInEnD0yKkjDAeZDS0A6bzhBH5hrMvTQ=
 github.com/xrash/smetrics v0.0.0-20240521201337-686a1a2994c1 h1:gEOO8jv9F4OT7lGCjxCBTO/36wtF6j2nSip77qHd4x4=
 github.com/xrash/smetrics v0.0.0-20240521201337-686a1a2994c1/go.mod h1:Ohn+xnUBiLI6FVj/9LpzZWtj1/D6lUovWYBkxHVV3aM=
 golang.org/x/text v0.22.0 h1:bofq7m3/HAFvbF51jz3Q9wLg3jkvSPuiZu/pD1XwgtM=
 golang.org/x/text v0.22.0/go.mod h1:YRoo4H8PVmsu+E3Ou7cqLVH8oXWIHVoX0jqUWALQhfY=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/sourcemap.v1 v1.0.5 h1:inv58fC9f9J3TK2Y2R1NPntXEn3/wjWHkonhIUODNTI=
+gopkg.in/sourcemap.v1 v1.0.5/go.mod h1:2RlvNNSMglmRrcvhfuzp4hQHwOtjxlbjX7UPY/GXb78=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

interpreter/template_interpreter.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 	"text/template"
 
+	"github.com/robertkrimen/otto"
 	"golang.org/x/text/cases"
 	"golang.org/x/text/language"
 	"gopkg.in/yaml.v3"
@@ -20,6 +21,7 @@ import (
 type TemplateManifest struct {
 	Name        string            `yaml:"name"`
 	Description string            `yaml:"description"`
+	Functions   map[string]string `yaml:"functions,omitempty"`
 	Outputs     []OutputFile      `yaml:"outputs"`
 }
 
@@ -35,12 +37,14 @@ type OutputFile struct {
 // TemplateInterpreter converts Masonry AST using template files
 type TemplateInterpreter struct {
 	registry *TemplateRegistry
+	vm       *otto.Otto
 }
 
 // NewTemplateInterpreter creates a new template interpreter
 func NewTemplateInterpreter() *TemplateInterpreter {
 	return &TemplateInterpreter{
 		registry: NewTemplateRegistry(),
+		vm:       otto.New(),
 	}
 }
 
@@ -115,13 +119,7 @@ func (ti *TemplateInterpreter) Interpret(masonryInput string, tmplText string) (
 
 // InterpretToFiles processes a manifest and returns multiple output files
 func (ti *TemplateInterpreter) InterpretToFiles(masonryFile, templateDir, manifestFile string) (map[string]string, error) {
-	// Load templates from directory
-	err := ti.registry.LoadFromDirectory(templateDir)
-	if err != nil {
-		return nil, fmt.Errorf("error loading templates: %w", err)
-	}
-
-	// Load manifest
+	// Load manifest first to get custom functions
 	manifestPath := filepath.Join(templateDir, manifestFile)
 	manifestData, err := os.ReadFile(manifestPath)
 	if err != nil {
@@ -134,6 +132,18 @@ func (ti *TemplateInterpreter) InterpretToFiles(masonryFile, templateDir, manife
 		return nil, fmt.Errorf("error parsing manifest: %w", err)
 	}
 
+	// Load custom JavaScript functions from the manifest BEFORE loading templates
+	err = ti.loadCustomFunctions(manifest.Functions)
+	if err != nil {
+		return nil, fmt.Errorf("error loading custom functions: %w", err)
+	}
+
+	// Now load templates from directory (they will have access to custom functions)
+	err = ti.registry.LoadFromDirectory(templateDir)
+	if err != nil {
+		return nil, fmt.Errorf("error loading templates: %w", err)
+	}
+
 	// Parse Masonry input
 	masonryInput, err := os.ReadFile(masonryFile)
 	if err != nil {
@@ -259,30 +269,31 @@ func (ti *TemplateInterpreter) getAllSections(ast lang.AST) []interface{} {
 
 	for _, def := range ast.Definitions {
 		if def.Page != nil {
-			// Get sections directly in the page
-			for i := range def.Page.Sections {
-				sections = append(sections, &def.Page.Sections[i])
-			}
+			// Get sections from page elements
+			for i := range def.Page.Elements {
+				element := &def.Page.Elements[i]
+				if element.Section != nil {
+					sections = append(sections, element.Section)
 					// Recursively get nested sections
-			sections = append(sections, ti.getSectionsFromSections(def.Page.Sections)...)
+					sections = append(sections, ti.getSectionsFromSection(*element.Section)...)
+				}
+			}
 		}
 	}
 
 	return sections
 }
 
-// getSectionsFromSections recursively extracts sections from a list of sections
-func (ti *TemplateInterpreter) getSectionsFromSections(sections []lang.Section) []interface{} {
+// getSectionsFromSection recursively extracts sections from a single section
+func (ti *TemplateInterpreter) getSectionsFromSection(section lang.Section) []interface{} {
 	var result []interface{}
 
-	for i := range sections {
-		for j := range sections[i].Elements {
-			element := &sections[i].Elements[j]
+	for i := range section.Elements {
+		element := &section.Elements[i]
 		if element.Section != nil {
 			result = append(result, element.Section)
 			// Recursively get sections from this section
-				result = append(result, ti.getSectionsFromSections([]lang.Section{*element.Section})...)
-			}
+			result = append(result, ti.getSectionsFromSection(*element.Section)...)
 		}
 	}
 
@@ -295,32 +306,17 @@ func (ti *TemplateInterpreter) getAllComponents(ast lang.AST) []interface{} {
 
 	for _, def := range ast.Definitions {
 		if def.Page != nil {
-			// Get components directly in the page
-			for i := range def.Page.Components {
-				components = append(components, &def.Page.Components[i])
-			}
-			// Get components from sections
-			components = append(components, ti.getComponentsFromSections(def.Page.Sections)...)
-		}
-	}
-
-	return components
-}
-
-// getComponentsFromSections recursively extracts components from sections
-func (ti *TemplateInterpreter) getComponentsFromSections(sections []lang.Section) []interface{} {
-	var components []interface{}
-
-	for i := range sections {
-		for j := range sections[i].Elements {
-			element := &sections[i].Elements[j]
+			// Get components from page elements
+			for i := range def.Page.Elements {
+				element := &def.Page.Elements[i]
 				if element.Component != nil {
 					components = append(components, element.Component)
 					// Get nested components from this component
-				components = append(components, ti.getComponentsFromComponents([]lang.Component{*element.Component})...)
+					components = append(components, ti.getComponentsFromComponent(*element.Component)...)
 				} else if element.Section != nil {
-				// Recursively get components from nested sections
-				components = append(components, ti.getComponentsFromSections([]lang.Section{*element.Section})...)
+					// Get components from sections
+					components = append(components, ti.getComponentsFromSection(*element.Section)...)
+				}
 			}
 		}
 	}
@@ -328,17 +324,34 @@ func (ti *TemplateInterpreter) getComponentsFromSections(sections []lang.Section
 	return components
 }
 
-// getComponentsFromComponents recursively extracts components from nested components
-func (ti *TemplateInterpreter) getComponentsFromComponents(components []lang.Component) []interface{} {
+// getComponentsFromSection recursively extracts components from a section
+func (ti *TemplateInterpreter) getComponentsFromSection(section lang.Section) []interface{} {
+	var components []interface{}
+
+	for i := range section.Elements {
+		element := &section.Elements[i]
+		if element.Component != nil {
+			components = append(components, element.Component)
+			// Get nested components from this component
+			components = append(components, ti.getComponentsFromComponent(*element.Component)...)
+		} else if element.Section != nil {
+			// Recursively get components from nested sections
+			components = append(components, ti.getComponentsFromSection(*element.Section)...)
+		}
+	}
+
+	return components
+}
+
+// getComponentsFromComponent recursively extracts components from nested components
+func (ti *TemplateInterpreter) getComponentsFromComponent(component lang.Component) []interface{} {
 	var result []interface{}
 
-	for i := range components {
-		for j := range components[i].Elements {
-			element := &components[i].Elements[j]
+	for i := range component.Elements {
+		element := &component.Elements[i]
 		if element.Section != nil {
 			// Get components from nested sections
-				result = append(result, ti.getComponentsFromSections([]lang.Section{*element.Section})...)
-			}
+			result = append(result, ti.getComponentsFromSection(*element.Section)...)
 		}
 	}
 
@@ -648,3 +661,107 @@ func (tr *TemplateRegistry) LoadFromDirectory(dir string) error {
 		return nil
 	})
 }
+
+// loadCustomFunctions loads JavaScript functions into the template function map
+func (ti *TemplateInterpreter) loadCustomFunctions(functions map[string]string) error {
+	if functions == nil {
+		return nil
+	}
+
+	for funcName, jsCode := range functions {
+		// Validate function name
+		if !isValidFunctionName(funcName) {
+			return fmt.Errorf("invalid function name: %s", funcName)
+		}
+
+		// Create a wrapper function that calls the JavaScript code
+		templateFunc := ti.createJavaScriptTemplateFunction(funcName, jsCode)
+		ti.registry.funcMap[funcName] = templateFunc
+	}
+
+	return nil
+}
+
+// createJavaScriptTemplateFunction creates a Go template function that executes JavaScript
+func (ti *TemplateInterpreter) createJavaScriptTemplateFunction(funcName, jsCode string) interface{} {
+	return func(args ...interface{}) (interface{}, error) {
+		// Create a new VM instance for this function call to avoid conflicts
+		vm := otto.New()
+
+		// Set up global helper functions in the JavaScript environment
+		vm.Set("log", func(call otto.FunctionCall) otto.Value {
+			// For debugging - could be extended to proper logging
+			fmt.Printf("[JS %s]: %v\n", funcName, call.ArgumentList)
+			return otto.UndefinedValue()
+		})
+
+		// Convert Go arguments to JavaScript values
+		for i, arg := range args {
+			vm.Set(fmt.Sprintf("arg%d", i), arg)
+		}
+
+		// Set a convenience 'args' array
+		argsArray, _ := vm.Object("args = []")
+		for i, arg := range args {
+			argsArray.Set(strconv.Itoa(i), arg)
+		}
+
+		// Execute the JavaScript function
+		jsWrapper := fmt.Sprintf(`
+			(function() {
+				%s
+				if (typeof main === 'function') {
+					return main.apply(this, args);
+				} else {
+					throw new Error('Custom function must define a main() function');
+				}
+			})();
+		`, jsCode)
+
+		result, err := vm.Run(jsWrapper)
+		if err != nil {
+			return nil, fmt.Errorf("error executing JavaScript function %s: %w", funcName, err)
+		}
+
+		// Convert JavaScript result back to Go value
+		if result.IsUndefined() || result.IsNull() {
+			return nil, nil
+		}
+
+		goValue, err := result.Export()
+		if err != nil {
+			return nil, fmt.Errorf("error converting JavaScript result to Go value: %w", err)
+		}
+
+		return goValue, nil
+	}
+}
+
+// isValidFunctionName checks if the function name is valid for Go templates
+func isValidFunctionName(name string) bool {
+	// Basic validation: alphanumeric and underscore, must start with letter
+	if len(name) == 0 {
+		return false
+	}
+
+	if !((name[0] >= 'a' && name[0] <= 'z') || (name[0] >= 'A' && name[0] <= 'Z') || name[0] == '_') {
+		return false
+	}
+
+	for _, char := range name[1:] {
+		if !((char >= 'a' && char <= 'z') || (char >= 'A' && char <= 'Z') ||
+			(char >= '0' && char <= '9') || char == '_') {
+			return false
+		}
+	}
+
+	// Avoid conflicts with built-in template functions
+	builtinFunctions := map[string]bool{
+		"and": true, "or": true, "not": true, "len": true, "index": true,
+		"print": true, "printf": true, "println": true, "html": true, "js": true,
+		"call": true, "urlquery": true, "eq": true, "ne": true, "lt": true,
+		"le": true, "gt": true, "ge": true,
+	}
+
+	return !builtinFunctions[name]
+}

readme.md

@@ -22,8 +22,8 @@ Masonry is a library that provides and implements all the basics necessary to bu
 
 - [x] Indicate values that are based on Environment variables
 - [x] On Entities, we should indicate what CRUD functions should be implemented instead of implementing all, or forcing the user to define each in the Endpoints section
-- [ ] Yaml file to include custom template functions (Otto for JS)
-- [ ] Support multi-file outputs based on a directory+manifest file.
+- [x] Yaml file to include custom template functions (Otto for JS)
+- [x] Support multi-file outputs based on a directory+manifest file.
 - [ ] Support multi-step generation. e.g. gen the proto file, use `masonry g` to get the basic server set up, gen `main.go` from a template, then update gorm overrides, etc.
 - [ ] Support field transformations on Entities using a template for `BeforeToORM` in `service.pb.gorm.override.go`