fix(fmt): Preserve newline after templ elements

parser/v2/formattestdata/element_double_newline_after_component.txt

@@ -0,0 +1,29 @@
+-- in --
+package main
+
+templ x() {
+	<div>
+		@Hero()
+		<span></span>
+
+
+		@Hero()
+
+
+
+		<span></span>
+	</div>
+}
+-- out --
+package main
+
+templ x() {
+	<div>
+		@Hero()
+		<span></span>
+
+		@Hero()
+
+		<span></span>
+	</div>
+}

parser/v2/templateparser_test.go

@@ -626,8 +626,8 @@ func TestTemplateParser(t *testing.T) {
 										},
 									},
 								},
+								TrailingSpace: SpaceHorizontal,
 							},
-							Whitespace{Value: " "},
 							Text{
 								Value: "Home",
 								Range: Range{

parser/v2/templelementparser.go

@@ -13,7 +13,11 @@ func (p templElementExpressionParser) Parse(pi *parse.Input) (n Node, ok bool, e
 		return
 	}
 
-	var r TemplElementExpression
+	r := TemplElementExpression{
+		// Default behavior is always a trailing space
+		TrailingSpace: SpaceVertical,
+	}
+
 	// Parse the Go expression.
 	if r.Expression, err = parseGo("templ element", pi, goexpression.TemplExpression); err != nil {
 		return r, false, err
@@ -26,6 +30,16 @@ func (p templElementExpressionParser) Parse(pi *parse.Input) (n Node, ok bool, e
 		return
 	}
 	if !hasOpenBrace {
+		// Parse trailing whitespace after expression.
+		ws, _, err := parse.Whitespace.Parse(pi)
+		if err != nil {
+			return r, false, err
+		}
+		r.TrailingSpace, err = NewTrailingSpace(ws, true)
+		if err != nil {
+			return r, false, err
+		}
+
 		return r, true, nil
 	}
 
@@ -46,6 +60,16 @@ func (p templElementExpressionParser) Parse(pi *parse.Input) (n Node, ok bool, e
 		return
 	}
 
+	// Parse trailing whitespace after closing brace.
+	ws, _, err := parse.Whitespace.Parse(pi)
+	if err != nil {
+		return r, false, err
+	}
+	r.TrailingSpace, err = NewTrailingSpace(ws, true)
+	if err != nil {
+		return r, false, err
+	}
+
 	return r, true, nil
 }
 

parser/v2/templelementparser_test.go

@@ -32,6 +32,7 @@ func TestTemplElementExpressionParser(t *testing.T) {
 						},
 					},
 				},
+				TrailingSpace: SpaceVertical,
 			},
 		},
 		{
@@ -53,6 +54,7 @@ func TestTemplElementExpressionParser(t *testing.T) {
 						},
 					},
 				},
+				TrailingSpace: SpaceVertical,
 			},
 		},
 		{
@@ -80,6 +82,7 @@ func TestTemplElementExpressionParser(t *testing.T) {
 						},
 					},
 				},
+				TrailingSpace: SpaceVertical,
 			},
 		},
 		{
@@ -190,8 +193,8 @@ func TestTemplElementExpressionParser(t *testing.T) {
 								To:   Position{28, 1, 11},
 							},
 						},
+						TrailingSpace: SpaceVertical,
 					},
-					Whitespace{Value: "\n\t\t\t"},
 				},
 			},
 		},
@@ -215,6 +218,7 @@ func TestTemplElementExpressionParser(t *testing.T) {
 						},
 					},
 				},
+				TrailingSpace: SpaceHorizontal,
 			},
 		},
 		{

parser/v2/types.go

@@ -956,6 +956,12 @@ type TemplElementExpression struct {
 	Expression Expression
 	// Children returns the elements in a block element.
 	Children []Node
+	// TrailingSpace lists what happens after the element.
+	TrailingSpace TrailingSpace
+}
+
+func (t TemplElementExpression) Trailing() TrailingSpace {
+	return t.TrailingSpace
 }
 
 func (tee TemplElementExpression) ChildNodes() []Node {