From 8f4bbde8a4412d628ab6ef38c510bf5e3242361a Mon Sep 17 00:00:00 2001
From: Simon Holthausen <simon.holthausen@accso.de>
Date: Fri, 25 Sep 2020 17:45:06 +0200
Subject: [PATCH] Support {#key} block

Needed for Svelte >2.28
---
 package-lock.json                   |  6 +++---
 package.json                        |  2 +-
 src/print/index.ts                  | 16 ++++++++++++++--
 src/print/nodes.ts                  |  7 +++++++
 test/printer/samples/key-block.html | 10 ++++++++++
 5 files changed, 35 insertions(+), 6 deletions(-)
 create mode 100644 test/printer/samples/key-block.html

diff --git a/package-lock.json b/package-lock.json
index 824e21a9..483011c1 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -4366,9 +4366,9 @@
             }
         },
         "svelte": {
-            "version": "3.22.2",
-            "resolved": "https://registry.npmjs.org/svelte/-/svelte-3.22.2.tgz",
-            "integrity": "sha512-DxumO0+vvHA6NSc2jtVty08I8lFI43q8P2zX6JxZL8J1kqK5NVjad6TRM/twhnWXC+QScnwkZ15O6X1aTsEKTA==",
+            "version": "3.28.0",
+            "resolved": "https://registry.npmjs.org/svelte/-/svelte-3.28.0.tgz",
+            "integrity": "sha512-WJW8wD+aTmU5GUnTUjdhVF35mve2MjylubLgB6fGWoXHpYENdwcwWsWvjMQLayzMynqNH733h1Ck8wJzNR7gdQ==",
             "dev": true
         },
         "symbol-observable": {
diff --git a/package.json b/package.json
index 2dbd27b6..bd857862 100644
--- a/package.json
+++ b/package.json
@@ -36,7 +36,7 @@
         "rollup-plugin-commonjs": "9.2.0",
         "rollup-plugin-node-resolve": "4.0.0",
         "rollup-plugin-typescript": "1.0.0",
-        "svelte": "^3.20.0",
+        "svelte": "^3.28.0",
         "ts-node": "^7.0.1",
         "tslib": "^1.9.3",
         "typescript": "3.2.4"
diff --git a/src/print/index.ts b/src/print/index.ts
index 8de00406..2a10f1fc 100644
--- a/src/print/index.ts
+++ b/src/print/index.ts
@@ -377,6 +377,18 @@ export function print(path: FastPath, options: ParserOptions, print: PrintFn): D
 
             return group(concat(block));
         }
+        case 'KeyBlock': {
+            const def: Doc[] = [
+                '{#key ',
+                printJS(path, print, 'expression'),
+                '}',
+                printIndentedWithNewlines(path, print),
+            ];
+
+            def.push('{/key}');
+
+            return concat([group(concat(def)), breakParent]);
+        }
         case 'ThenBlock':
         case 'PendingBlock':
         case 'CatchBlock':
@@ -439,7 +451,7 @@ export function print(path: FastPath, options: ParserOptions, print: PrintFn): D
         case 'Comment': {
             /**
              * If there is no sibling node that starts right after us but the parent indicates
-             * that there used to be, that means that node was actually an embedded `<style>` 
+             * that there used to be, that means that node was actually an embedded `<style>`
              * or `<script>` node that was cut out.
              * If so, the comment does not refer to the next line we will see.
              * The `embed` function handles printing the comment in the right place.
@@ -545,7 +557,7 @@ function printChildren(path: FastPath, print: PrintFn): Doc[] {
      */
     function outputChildDoc(childDoc?: Doc, fromNode?: Node) {
         if (!isPreformat) {
-            if ((!childDoc || !fromNode || canBreakBefore(fromNode))) {
+            if (!childDoc || !fromNode || canBreakBefore(fromNode)) {
                 linebreakPossible();
 
                 const lastChild = childDocs[childDocs.length - 1];
diff --git a/src/print/nodes.ts b/src/print/nodes.ts
index dced6e75..38861eff 100644
--- a/src/print/nodes.ts
+++ b/src/print/nodes.ts
@@ -76,6 +76,12 @@ export interface AwaitBlockNode extends BaseNode {
     catch: CatchBlockNode;
 }
 
+export interface KeyBlockNode extends BaseNode {
+    type: 'KeyBlock';
+    expression: Node;
+    children: Node[];
+}
+
 export interface ThenBlockNode extends BaseNode {
     type: 'ThenBlock';
     children: Node[];
@@ -257,6 +263,7 @@ export type Node =
     | ElseBlockNode
     | EachBlockNode
     | AwaitBlockNode
+    | KeyBlockNode
     | ThenBlockNode
     | PendingBlockNode
     | CatchBlockNode
diff --git a/test/printer/samples/key-block.html b/test/printer/samples/key-block.html
new file mode 100644
index 00000000..b5084ec2
--- /dev/null
+++ b/test/printer/samples/key-block.html
@@ -0,0 +1,10 @@
+{#key value}
+    <p>hello</p>
+    <p>hello</p>
+{/key}
+{#key $store}
+    <p>hello</p>
+{/key}
+{#key expr.obj}
+    <p>hello</p>
+{/key}