From 7c9b31be0fd6ee2bfd6073d3c2d6eb66b776ad88 Mon Sep 17 00:00:00 2001
From: Tan Li Hau <lhtan93@gmail.com>
Date: Sat, 19 Sep 2020 10:25:07 +0800
Subject: [PATCH] sequence expression instead of identity function

---
 src/compiler/compile/render_ssr/index.ts         | 11 +++++++++--
 .../store-auto-resubscribe-immediate/main.svelte | 16 ++++++++++++----
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/src/compiler/compile/render_ssr/index.ts b/src/compiler/compile/render_ssr/index.ts
index 8ca7663e7091..b395a5973744 100644
--- a/src/compiler/compile/render_ssr/index.ts
+++ b/src/compiler/compile/render_ssr/index.ts
@@ -5,7 +5,7 @@ import { string_literal } from '../utils/stringify';
 import Renderer from './Renderer';
 import { INode as TemplateNode } from '../nodes/interfaces'; // TODO
 import Text from '../nodes/Text';
-import { LabeledStatement, Statement, Node } from 'estree';
+import { LabeledStatement, Statement, Node, Expression } from 'estree';
 import { walk } from 'estree-walker';
 import { extract_names } from 'periscopic';
 
@@ -99,7 +99,14 @@ export default function ssr(
 						});
 
 					if (vars.length) {
-						this.replace(x`@identity(${node}, ${vars})`);
+						this.replace({
+							type: 'SequenceExpression',
+							expressions: [
+								node,
+								...vars,
+								assignee as Expression
+							]
+						});
 					}
 				}
 			}
diff --git a/test/runtime/samples/store-auto-resubscribe-immediate/main.svelte b/test/runtime/samples/store-auto-resubscribe-immediate/main.svelte
index f402662a53e2..10721c4b4957 100644
--- a/test/runtime/samples/store-auto-resubscribe-immediate/main.svelte
+++ b/test/runtime/samples/store-auto-resubscribe-immediate/main.svelte
@@ -8,16 +8,24 @@
 	// should resubscribe immediately
 	value = writable({ foo: $value.foo + 2, bar: $value.bar - 2 }); // { foo: 5, bar: 4 }
 	
+	// should mutate the store value
 	$value.baz = $value.foo + $value.bar; // { foo: 5, bar: 4, baz: 9 }
 	
 	// should resubscribe immediately
 	value = writable({ qux: $value.baz - $value.foo }); // { qux: 4 }
 
-	// should update the store immediately
-	$value = { baz: $value.qux }; // { baz: 4 }
+	// making sure instrumentation returns the expression value
+	$value = {
+		one: writable(
+			$value = {
+				two: ({ $value } = { '$value': { fred: $value.qux } }) // { fred: 4 }
+			}, // { two: { $value: { fred: 4 } } }
+		), // { one: { two: { $value: { fred: 4 } } } }
+	};
 
-	value.update(val => ({ answer: val.baz })); // { answer: 4 }
-	value = value; // for ssr
+	const one = $value.one;
+
+	value.update(val => ({ answer: $one.two.$value.fred })); // { answer: 4 }
 </script>
 
 {JSON.stringify($value)}
\ No newline at end of file