Support FixedIndent, add tests

template_nest.go

@@ -16,11 +16,12 @@ type Hash map[string]interface{}
 type Option struct {
 	Delimiters        [2]string
 	NameLabel         string    // Identify the template to be used
-	TemplateDir       string    // directory where templates are located
-	TemplateExtension string    // appended on the label to idenfity the template
-	DieOnBadParams    bool      // attempt to populate a variable that doesn't exist should result in an error
+	TemplateDir       string    // Directory where templates are located
+	TemplateExtension string    // Appended on the label to idenfity the template
+	DieOnBadParams    bool      // Attempt to populate a variable that doesn't exist should result in an error
 	ShowLabels        bool      // Prepend & Append a string to every template, helpful in debugging
 	CommentDelimiters [2]string // Used in conjunction with ShowLabels, if HTML then use '<!--', '-->'
+	FixedIndent       bool      // Intended to improve readability when inspecting nested templates
 }
 
 type TemplateNest struct {
@@ -118,6 +119,7 @@ func (nest *TemplateNest) index(filePath string) (TemplateFileIndex, error) {
 	if err != nil {
 		return TemplateFileIndex{}, fmt.Errorf("error reading file (`%s`): %w", filePath, err)
 	}
+
 	// Capture last modified time
 	fileInfo, err := os.Stat(filePath)
 	if err != nil {
@@ -134,6 +136,7 @@ func (nest *TemplateNest) index(filePath string) (TemplateFileIndex, error) {
 		"%s\\s*(.+?)\\s*%s", regexp.QuoteMeta(delimiterStart), regexp.QuoteMeta(delimiterEnd),
 	))
 
+	contentsStr := string(contents)
 	matches := re.FindAllStringSubmatchIndex(string(contents), -1)
 	for _, match := range matches {
 		if len(match) < 4 {
@@ -148,15 +151,33 @@ func (nest *TemplateNest) index(filePath string) (TemplateFileIndex, error) {
 		varName := string(contents[nameStartIdx:nameEndIdx])
 		variableNames[varName] = struct{}{}
 
+		// If fixed indent is enabled then record the indent level for this
+		// variable. To get the indent level we look at each character in
+		// reverse from the start position of the variable until we find a
+		// newline character.
+		indentLevel := 0
+		if nest.option.FixedIndent {
+			// If we do not encounter a newline then that means this variable is
+			// on the first line, we take the start position as the indent
+			// level.
+			lineStartIdx := strings.LastIndex(contentsStr[:startIdx], "\n")
+			if lineStartIdx == -1 {
+				indentLevel = startIdx
+			} else {
+				indentLevel = startIdx - lineStartIdx - 1
+			}
+		}
+
 		variables = append(variables, TemplateFileVariable{
 			Name:          varName,
 			StartPosition: uint(startIdx),
 			EndPosition:   uint(endIdx),
+			IndentLevel:   uint(indentLevel),
 		})
 	}
 
 	fileIndex := TemplateFileIndex{
-		Contents:      string(contents),
+		Contents:      contentsStr,
 		LastModified:  fileInfo.ModTime(),
 		VariableNames: variableNames,
 		Variables:     variables,
@@ -261,15 +282,17 @@ func (nest *TemplateNest) Render(toRender interface{}) (string, error) {
 			replacement := ""
 
 			if value, exists := v[variable.Name]; exists {
-				if text, ok := value.(string); ok {
-					replacement = text
-				} else {
-					subRender, err := nest.Render(value)
-					if err != nil {
-						return "", err
-					}
-					replacement = subRender
+				subRender, err := nest.Render(value)
+				if err != nil {
+					return "", err
 				}
+
+				if nest.option.FixedIndent && variable.IndentLevel != 0 {
+					indentReplacement := "\n" + strings.Repeat(" ", int(variable.IndentLevel))
+					subRender = strings.ReplaceAll(subRender, "\n", indentReplacement)
+				}
+
+				replacement = subRender
 			}
 
 			// Replace in rendered template

tests/05_fixed_indent_test.go

@@ -0,0 +1,92 @@
+package tests
+
+import (
+	"git.virtual.blue/tomgracey/template-nest-go"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestRenderSimplePageWithFixedIndent(t *testing.T) {
+	nest, err := templatenest.New(templatenest.Option{
+		TemplateDir: "templates",
+		FixedIndent: true,
+	})
+	if err != nil {
+		t.Fatalf("Failed to initialize TemplateNest: %+v", err)
+	}
+
+	page := templatenest.Hash{
+		"TEMPLATE": "00-simple-page",
+		"variable": "Simple Variable",
+		"simple_component": templatenest.Hash{
+			"TEMPLATE": "02-simple-component-multi-line",
+		},
+	}
+	outputPage := templatenest.Hash{"TEMPLATE": "output/07-simple-page-fixed-indent"}
+
+	render := nest.MustRender(page)
+	outputRender := nest.MustRender(outputPage)
+
+	assert.Equal(t, outputRender, render, "Rendered output does not match expected output")
+}
+
+func TestRenderComplexPageWithFixedIndent(t *testing.T) {
+	nest, err := templatenest.New(templatenest.Option{
+		TemplateDir: "templates",
+		FixedIndent: true,
+	})
+	if err != nil {
+		t.Fatalf("Failed to initialize TemplateNest: %+v", err)
+	}
+
+	page := templatenest.Hash{
+		"TEMPLATE": "10-complex-page",
+		"title":    "Complex Page",
+		"pre_body": templatenest.Hash{
+			"TEMPLATE": "18-styles",
+		},
+		"navigation": templatenest.Hash{
+			"TEMPLATE": "11-navigation",
+			"banner": templatenest.Hash{
+				"TEMPLATE": "12-navigation-banner",
+			},
+			"items": []templatenest.Hash{
+				templatenest.Hash{"TEMPLATE": "13-navigation-item-00-services"},
+				templatenest.Hash{"TEMPLATE": "13-navigation-item-01-resources"},
+			},
+		},
+		"hero_section": templatenest.Hash{
+			"TEMPLATE": "14-hero-section",
+		},
+		"main_content": []templatenest.Hash{
+			templatenest.Hash{"TEMPLATE": "15-isdc-card"},
+			templatenest.Hash{
+				"TEMPLATE": "16-vb-brand-cards",
+				"cards": []templatenest.Hash{
+					templatenest.Hash{
+						"TEMPLATE":       "17-vb-brand-card-00",
+						"parent_classes": "p-card brand-card col-4",
+					},
+					templatenest.Hash{
+						"TEMPLATE":       "17-vb-brand-card-01",
+						"parent_classes": "p-card brand-card col-4",
+					},
+					templatenest.Hash{
+						"TEMPLATE":       "17-vb-brand-card-02",
+						"parent_classes": "p-card brand-card col-4",
+					},
+				},
+			},
+		},
+		"post_footer": templatenest.Hash{
+			"TEMPLATE": "19-scripts",
+		},
+	}
+
+	outputPage := templatenest.Hash{"TEMPLATE": "output/08-complex-page-fixed-indent"}
+
+	render := nest.MustRender(page)
+	outputRender := nest.MustRender(outputPage)
+
+	assert.Equal(t, outputRender, render, "Rendered output does not match expected output")
+}