diff --git a/src/generators/dom/index.ts b/src/generators/dom/index.ts
index 2dd54ac83e..63778addb5 100644
--- a/src/generators/dom/index.ts
+++ b/src/generators/dom/index.ts
@@ -335,7 +335,7 @@ export default function dom(
 			}
 
 			customElements.define("${generator.tag}", ${name});
-			@assign(${prototypeBase}, ${proto}, {
+			@assign(@assign(${prototypeBase}, ${proto}), {
 				_mount(target, anchor) {
 					target.insertBefore(this, anchor);
 				},
diff --git a/src/generators/nodes/AwaitBlock.ts b/src/generators/nodes/AwaitBlock.ts
index 8cfa0a49e4..02847d93d6 100644
--- a/src/generators/nodes/AwaitBlock.ts
+++ b/src/generators/nodes/AwaitBlock.ts
@@ -125,7 +125,7 @@ export default class AwaitBlock extends Node {
 						${this.then.block.context ? deindent`
 							var state = #component.get();
 							${resolved} = { ${this.then.block.context}: ${value} };
-							${replace_await_block}(${token}, ${create_then_block}, @assign({}, state, ${resolved}));
+							${replace_await_block}(${token}, ${create_then_block}, @assign(@assign({}, state), ${resolved}));
 						` : deindent`
 							${replace_await_block}(${token}, null, null);
 						`}
@@ -133,7 +133,7 @@ export default class AwaitBlock extends Node {
 						${this.catch.block.context ? deindent`
 							var state = #component.get();
 							${resolved} = { ${this.catch.block.context}: ${error} };
-							${replace_await_block}(${token}, ${create_catch_block}, @assign({}, state, ${resolved}));
+							${replace_await_block}(${token}, ${create_catch_block}, @assign(@assign({}, state), ${resolved}));
 						` : deindent`
 							${replace_await_block}(${token}, null, null);
 						`}
@@ -147,7 +147,7 @@ export default class AwaitBlock extends Node {
 				} else {
 					${resolved} = { ${this.then.block.context}: ${promise} };
 					if (${await_block_type} !== ${create_then_block}) {
-						${replace_await_block}(${token}, ${create_then_block}, @assign({}, state, ${resolved}));
+						${replace_await_block}(${token}, ${create_then_block}, @assign(@assign({}, state), ${resolved}));
 						return true;
 					}
 				}
@@ -190,7 +190,7 @@ export default class AwaitBlock extends Node {
 				if (${conditions.join(' && ')}) {
 					// nothing
 				} else {
-					${await_block}.p(changed, @assign({}, state, ${resolved}));
+					${await_block}.p(changed, @assign(@assign({}, state), ${resolved}));
 				}
 			`);
 		} else {
@@ -217,4 +217,4 @@ export default class AwaitBlock extends Node {
 			});
 		});
 	}
-}
\ No newline at end of file
+}
diff --git a/src/generators/nodes/EachBlock.ts b/src/generators/nodes/EachBlock.ts
index 55e1ea87e8..1eb1d8cb7a 100644
--- a/src/generators/nodes/EachBlock.ts
+++ b/src/generators/nodes/EachBlock.ts
@@ -267,7 +267,7 @@ export default class EachBlock extends Node {
 		block.builders.init.addBlock(deindent`
 			for (var #i = 0; #i < ${each_block_value}.${length}; #i += 1) {
 				var ${key} = ${each_block_value}[#i].${this.key};
-				${blocks}[#i] = ${lookup}[${key}] = ${create_each_block}(#component, ${key}, @assign({}, state, {
+				${blocks}[#i] = ${lookup}[${key}] = ${create_each_block}(#component, ${key}, @assign(@assign({}, state), {
 					${this.contextProps.join(',\n')}
 				}));
 			}
@@ -297,7 +297,7 @@ export default class EachBlock extends Node {
 			var ${each_block_value} = ${snippet};
 
 			${blocks} = @updateKeyedEach(${blocks}, #component, changed, "${this.key}", ${dynamic}, ${each_block_value}, ${lookup}, ${updateMountNode}, ${String(this.block.hasOutroMethod)}, ${create_each_block}, "${mountOrIntro}", function(#i) {
-				return @assign({}, state, {
+				return @assign(@assign({}, state), {
 					${this.contextProps.join(',\n')}
 				});
 			});
@@ -332,7 +332,7 @@ export default class EachBlock extends Node {
 			var ${iterations} = [];
 
 			for (var #i = 0; #i < ${each_block_value}.${length}; #i += 1) {
-				${iterations}[#i] = ${create_each_block}(#component, @assign({}, state, {
+				${iterations}[#i] = ${create_each_block}(#component, @assign(@assign({}, state), {
 					${this.contextProps.join(',\n')}
 				}));
 			}
@@ -430,7 +430,7 @@ export default class EachBlock extends Node {
 
 				if (${condition}) {
 					for (var #i = ${start}; #i < ${each_block_value}.${length}; #i += 1) {
-						var ${this.each_context} = @assign({}, state, {
+						var ${this.each_context} = @assign(@assign({}, state), {
 							${this.contextProps.join(',\n')}
 						});
 
diff --git a/src/shared/index.js b/src/shared/index.js
index a410e7d9df..d73d0979e1 100644
--- a/src/shared/index.js
+++ b/src/shared/index.js
@@ -163,7 +163,7 @@ export function _set(newState) {
 	}
 	if (!dirty) return;
 
-	this._state = assign({}, oldState, newState);
+	this._state = assign(assign({}, oldState), newState);
 	this._recompute(changed, this._state);
 	if (this._bind) this._bind(changed, this._state);