preserve empty lines between jinja elements

src/jinja.ts

@@ -5,9 +5,9 @@ export const Placeholder = {
 
 export interface Node {
 	id: string;
-	type: "root" | "expression" | "statement" | "block" | "ignore";
+	type: "root" | "expression" | "statement" | "block" | "comment" | "ignore";
 	content: string;
-	ownLine: boolean;
+	preNewLines: number;
 	originalText: string;
 	index: number;
 	length: number;
@@ -31,10 +31,7 @@ export interface Block extends Node {
 	type: "block";
 	start: Statement;
 	end: Statement;
-}
+	containsNewLines: boolean;
-
-export interface IgnoreBlock extends Node {
-	type: "ignore";
 }
 
 export const nonClosingStatements = [

src/parser.ts

@@ -12,7 +12,7 @@ import {
 const NOT_FOUND = -1;
 
 const regex =
-	/(?<pre>(?<newline>\n)?(\s*?))(?<node>{{(?<startDelimiterEx>[-+]?)\s*(?<expression>'([^']|\\')*'|"([^"]|\\")*"|[\S\s]*?)\s*(?<endDelimiterEx>[-+]?)}}|{%(?<startDelimiter>[-+]?)\s*(?<statement>(?<keyword>\w+)('([^']|\\')*'|"([^"]|\\")*"|[\S\s])*?)\s*(?<endDelimiter>[-+]?)%}|(?<comment>{#[\S\s]*?#})|(?<scriptBlock><(script)((?!<)[\s\S])*>((?!<\/script)[\s\S])*?{{[\s\S]*?<\/(script)>)|(?<styleBlock><(style)((?!<)[\s\S])*>((?!<\/style)[\s\S])*?{{[\s\S]*?<\/(style)>)|(?<ignoreBlock><!-- prettier-ignore-start -->[\s\S]*<!-- prettier-ignore-end -->))/;
+	/(?<node>{{(?<startDelimiterEx>[-+]?)\s*(?<expression>'([^']|\\')*'|"([^"]|\\")*"|[\S\s]*?)\s*(?<endDelimiterEx>[-+]?)}}|{%(?<startDelimiter>[-+]?)\s*(?<statement>(?<keyword>\w+)('([^']|\\')*'|"([^"]|\\")*"|[\S\s])*?)\s*(?<endDelimiter>[-+]?)%}|(?<comment>{#[\S\s]*?#})|(?<scriptBlock><(script)((?!<)[\s\S])*>((?!<\/script)[\s\S])*?{{[\s\S]*?<\/(script)>)|(?<styleBlock><(style)((?!<)[\s\S])*>((?!<\/style)[\s\S])*?{{[\s\S]*?<\/(style)>)|(?<ignoreBlock><!-- prettier-ignore-start -->[\s\S]*<!-- prettier-ignore-end -->))/;
 
 export const parse: Parser<Node>["parse"] = (text) => {
 	const statementStack: Statement[] = [];
@@ -21,7 +21,7 @@ export const parse: Parser<Node>["parse"] = (text) => {
 		id: "0",
 		type: "root" as const,
 		content: text,
-		ownLine: false,
+		preNewLines: 0,
 		originalText: text,
 		index: 0,
 		length: 0,
@@ -44,9 +44,6 @@ export const parse: Parser<Node>["parse"] = (text) => {
 			continue;
 		}
 
-		const pre = match.groups.pre || "";
-		const newline = !!match.groups.newline;
-
 		const matchText = match.groups.node;
 		const expression = match.groups.expression;
 		const statement = match.groups.statement;
@@ -58,21 +55,28 @@ export const parse: Parser<Node>["parse"] = (text) => {
 		}
 		const placeholder = generatePlaceholder();
 
+		const emptyLinesBetween = text.slice(i, i + match.index).match(/^\s+$/) || [
+			"",
+		];
+		const preNewLines = emptyLinesBetween.length
+			? emptyLinesBetween[0].split("\n").length - 1
+			: 0;
+
 		const node = {
 			id: placeholder,
-			ownLine: newline,
+			preNewLines,
 			originalText: matchText,
-			index: match.index + i + pre.length,
+			index: match.index + i,
 			length: matchText.length,
 			nodes: root.nodes,
 		};
 
-		if (ignoreBlock || comment) {
+		if (comment || ignoreBlock) {
 			root.content = root.content.replace(matchText, placeholder);
 			root.nodes[node.id] = {
 				...node,
-				type: "ignore",
+				type: comment ? "comment" : "ignore",
-				content: ignoreBlock || comment,
+				content: comment || ignoreBlock,
 			};
 		}
 
@@ -158,7 +162,8 @@ export const parse: Parser<Node>["parse"] = (text) => {
 					start: start,
 					end: end,
 					content: blockText.slice(start.length, blockText.length - end.length),
-					ownLine: originalText.search("\n") !== NOT_FOUND,
+					preNewLines: start.preNewLines,
+					containsNewLines: originalText.search("\n") !== NOT_FOUND,
 					originalText,
 					index: start.index,
 					length: end.index + end.length - start.index,

src/printer.ts

@@ -1,13 +1,6 @@
-import { Printer } from "prettier";
+import { AstPath, Printer } from "prettier";
 import { builders, utils } from "prettier/doc";
-import {
+import { Placeholder, Node, Expression, Statement, Block } from "./jinja";
-	Placeholder,
-	Node,
-	Expression,
-	Statement,
-	Block,
-	IgnoreBlock,
-} from "./jinja";
 
 const NOT_FOUND = -1;
 
@@ -24,8 +17,10 @@ export const print: Printer<Node>["print"] = (path) => {
 			return printExpression(node as Expression);
 		case "statement":
 			return printStatement(node as Statement);
+		case "comment":
+			return printCommentBlock(node);
 		case "ignore":
-			return printIgnoreBlock(node as IgnoreBlock);
+			return printIgnoreBlock(node);
 	}
 	return [];
 };
@@ -33,20 +28,24 @@ export const print: Printer<Node>["print"] = (path) => {
 const printExpression = (node: Expression): builders.Doc => {
 	const multiline = node.content.includes("\n");
 
-	return builders.group(
+	const expression = builders.group(
 		builders.join(" ", [
 			["{{", node.delimiter],
 			multiline
-				? builders.indent([getMultilineGroup(node.content)])
+				? builders.indent(getMultilineGroup(node.content))
 				: node.content,
 			multiline
 				? [builders.hardline, node.delimiter, "}}"]
 				: [node.delimiter, "}}"],
 		]),
 		{
-			shouldBreak: node.ownLine,
+			shouldBreak: node.preNewLines > 0,
 		}
 	);
+
+	return node.preNewLines > 1
+		? builders.group([builders.hardline, builders.trim, expression])
+		: expression;
 };
 
 const printStatement = (node: Statement): builders.Doc => {
@@ -62,20 +61,30 @@ const printStatement = (node: Statement): builders.Doc => {
 				? [builders.hardline, node.delimiter, "%}"]
 				: [node.delimiter, "%}"],
 		]),
-		{ shouldBreak: node.ownLine }
+		{ shouldBreak: node.preNewLines > 0 }
 	);
 
 	if (
 		["else", "elif"].includes(node.keyword) &&
-		surroundingBlock(node)?.ownLine
+		surroundingBlock(node)?.containsNewLines
 	) {
 		return [builders.dedent(builders.hardline), statemnt, builders.hardline];
 	}
 	return statemnt;
 };
 
-const printIgnoreBlock = (node: IgnoreBlock): builders.Doc => {
+const printCommentBlock = (node: Node): builders.Doc => {
-	return builders.group(node.content, { shouldBreak: node.ownLine });
+	const comment = builders.group(node.content, {
+		shouldBreak: node.preNewLines > 0,
+	});
+
+	return node.preNewLines > 1
+		? builders.group([builders.hardline, builders.trim, comment])
+		: comment;
+};
+
+const printIgnoreBlock = (node: Node): builders.Doc => {
+	return node.content;
 };
 
 export const embed: Printer<Node>["embed"] = (
@@ -150,22 +159,11 @@ export const embed: Printer<Node>["embed"] = (
 	});
 
 	if (node.type === "block") {
-		if (node.content.includes("\n")) {
+		const block = buildBlock(path, print, node as Block, mapped);
-			return builders.group([
+
-				path.call(print, "nodes", (node as Block).start.id),
+		return node.preNewLines > 1
-				builders.indent([
+			? builders.group([builders.hardline, builders.trim, block])
-					builders.softline,
+			: block;
-					utils.stripTrailingHardline(mapped),
-				]),
-				builders.hardline,
-				path.call(print, "nodes", (node as Block).end.id),
-			]);
-		}
-		return builders.group([
-			path.call(print, "nodes", (node as Block).start.id),
-			utils.stripTrailingHardline(mapped),
-			path.call(print, "nodes", (node as Block).end.id),
-		]);
 	}
 	return [...mapped, builders.hardline];
 };
@@ -223,3 +221,24 @@ export const surroundingBlock = (node: Node): Block | undefined => {
 		(n) => n.type === "block" && n.content.search(node.id) !== NOT_FOUND
 	) as Block;
 };
+
+const buildBlock = (
+	path: AstPath<Node>,
+	print: (path: AstPath<Node>) => builders.Doc,
+	block: Block,
+	mapped: (string | builders.Doc[] | builders.DocCommand)[]
+): builders.Doc => {
+	if (block.containsNewLines) {
+		return builders.group([
+			path.call(print, "nodes", block.start.id),
+			builders.indent([builders.softline, utils.stripTrailingHardline(mapped)]),
+			builders.hardline,
+			path.call(print, "nodes", block.end.id),
+		]);
+	}
+	return builders.group([
+		path.call(print, "nodes", block.start.id),
+		utils.stripTrailingHardline(mapped),
+		path.call(print, "nodes", block.end.id),
+	]);
+};

test/cases/expression/expected.html

@@ -1,5 +1,3 @@
-<div>
+<div>{{ user.name }}</div>
-  {{ user.name }}
-</div>
 
 <div>{{ user.age }}</div>

test/cases/newline_between/expected.html

@@ -0,0 +1,30 @@
+{% extends "base.html" %}
+
+{% block title %}Index{% endblock %}
+
+{% block head %}
+  {{ super() }}
+  <style type="text/css">
+    .important {
+      color: #336699;
+    }
+  </style>
+{% endblock %}
+
+{{ title }}
+
+{# content #}
+{% block content %}
+  <h1>Index</h1>
+  <p class="important">Welcome to my awesome homepage.</p>
+{% endblock %}
+
+<div></div>
+
+{{ name }}
+
+{% for user in users %}
+  <li>{{ user.username|e }}</li>
+{% else %}
+  <li><em>no users found</em></li>
+{% endfor %}

test/cases/newline_between/input.html

@@ -0,0 +1,39 @@
+{% extends "base.html" %}
+	
+    
+	{% block title %}Index{% endblock %}
+    
+	
+{% block head %}
+    {{ super() }}
+    <style type="text/css">
+        .important { color: #336699; }
+    </style>
+{% endblock %}
+	
+    
+{{title}}
+    
+	
+{# content #}
+{% block content %}
+    <h1>Index</h1>
+    <p class="important">
+      Welcome to my awesome homepage.
+    </p>
+  
+{% endblock %}
+
+<div></div>
+
+{{name}}
+
+
+{% for user in users %}
+    <li>{{ user.username|e }}</li>
+
+
+	{% else %}
+    <li><em>no users found</em></li>
+
+	{% endfor %}