feat: support insert/require pragma options (#354)

closes #350

Author: dummdidumm

CHANGELOG.md

@@ -1,5 +1,9 @@
 # prettier-plugin-svelte changelog
 
+## 2.10.0 (unreleased)
+
+-   (feat) support `requirePragma` and `insertPragma` options
+
 ## 2.9.0
 
 -   (feat) support style modifiers ([#330](https://github.com/sveltejs/prettier-plugin-svelte/issues/330))

src/index.ts

@@ -1,5 +1,5 @@
 import { SupportLanguage, Parser, Printer } from 'prettier';
-import { print } from './print';
+import { hasPragma, print } from './print';
 import { ASTNode } from './print/nodes';
 import { embed } from './embed';
 import { snipScriptAndStyleTagContent } from './lib/snipTagContent';
@@ -23,6 +23,7 @@ export const languages: Partial<SupportLanguage>[] = [
 
 export const parsers: Record<string, Parser> = {
     svelte: {
+        hasPragma,
         parse: (text) => {
             try {
                 return <ASTNode>{ ...require(`svelte/compiler`).parse(text), __isRoot: true };

src/print/index.ts

@@ -83,6 +83,10 @@ declare module 'prettier' {
     }
 }
 
+export function hasPragma(text: string) {
+    return /^\s*<!--\s*@(format|prettier)\W/.test(text);
+}
+
 let ignoreNext = false;
 let ignoreRange = false;
 let svelteOptionsDoc: Doc | undefined;
@@ -772,7 +776,13 @@ function printTopLevelParts(
                 delete topLevelPartsByEnd[node.start];
             }
         }
-        return path.call(print, 'html');
+
+        const result = path.call(print, 'html');
+        if (options.insertPragma && !hasPragma(options.originalText)) {
+            return concat([`<!-- @format -->`, hardline, result]);
+        } else {
+            return result;
+        }
     }
 
     const parts: Record<SortOrderPart, Doc[]> = {
@@ -826,7 +836,11 @@ function printTopLevelParts(
         trimRight([lastDoc], isLine);
     }
 
-    return groupConcat([join(hardline, docs)]);
+    if (options.insertPragma && !hasPragma(options.originalText)) {
+        return concat([`<!-- @format -->`, hardline, groupConcat(docs)]);
+    } else {
+        return groupConcat([join(hardline, docs)]);
+    }
 }
 
 function printAttributeNodeValue(

test/formatting/samples/insert-pragma/input.html

@@ -0,0 +1,4 @@
+<p>
+    format
+    me
+</p>

test/formatting/samples/insert-pragma/options.json

@@ -0,0 +1,3 @@
+{
+    "insertPragma": true
+}

test/formatting/samples/insert-pragma/output.html

@@ -0,0 +1,2 @@
+<!-- @format -->
+<p>format me</p>

test/formatting/samples/require-pragma-present/input.html

@@ -0,0 +1,5 @@
+<!-- @format -->
+<p>
+    format
+    me
+</p>

test/formatting/samples/require-pragma-present/options.json

@@ -0,0 +1,3 @@
+{
+    "requirePragma": true
+}

test/formatting/samples/require-pragma-present/output.html

@@ -0,0 +1,2 @@
+<!-- @format -->
+<p>format me</p>

test/printer/samples/insert-pragma-present.html

@@ -0,0 +1,2 @@
+<!-- @format -->
+<p>already formatted</p>

test/printer/samples/insert-pragma-present.options.json

@@ -0,0 +1,3 @@
+{
+    "insertPragma": true
+}

test/printer/samples/require-pragma-missing.html

@@ -0,0 +1,5 @@
+<p>
+
+
+    nope
+</p>

test/printer/samples/require-pragma-missing.options.json

@@ -0,0 +1,3 @@
+{
+    "requirePragma": true
+}