diff --git a/test/js/samples/action-custom-event-handler/expected.js b/test/js/samples/action-custom-event-handler/expected.js
index cac2f61b4450..0ea6c4644248 100644
--- a/test/js/samples/action-custom-event-handler/expected.js
+++ b/test/js/samples/action-custom-event-handler/expected.js
@@ -6,6 +6,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	is_function,
 	noop,
 	safe_not_equal
@@ -56,6 +57,7 @@ function instance($$self, $$props, $$invalidate) {
 	const foo_function = () => handleFoo(bar);
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("bar" in $$props) $$invalidate(0, bar = $$props.bar);
 	};
 
diff --git a/test/js/samples/bind-open/expected.js b/test/js/samples/bind-open/expected.js
index 30387d505db9..ed7830f7c22a 100644
--- a/test/js/samples/bind-open/expected.js
+++ b/test/js/samples/bind-open/expected.js
@@ -5,6 +5,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	listen,
 	noop,
 	safe_not_equal
@@ -53,6 +54,7 @@ function instance($$self, $$props, $$invalidate) {
 	}
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("open" in $$props) $$invalidate(0, open = $$props.open);
 	};
 
diff --git a/test/js/samples/bind-width-height/expected.js b/test/js/samples/bind-width-height/expected.js
index 4848704c4b0d..31c9774f5b0f 100644
--- a/test/js/samples/bind-width-height/expected.js
+++ b/test/js/samples/bind-width-height/expected.js
@@ -7,6 +7,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal
 } from "svelte/internal";
@@ -47,6 +48,7 @@ function instance($$self, $$props, $$invalidate) {
 	}
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("w" in $$props) $$invalidate(0, w = $$props.w);
 		if ("h" in $$props) $$invalidate(1, h = $$props.h);
 	};
diff --git a/test/js/samples/bindings-readonly-order/expected.js b/test/js/samples/bindings-readonly-order/expected.js
index 0e845c65b8f4..59006ab565c5 100644
--- a/test/js/samples/bindings-readonly-order/expected.js
+++ b/test/js/samples/bindings-readonly-order/expected.js
@@ -6,6 +6,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	listen,
 	noop,
 	run_all,
@@ -69,6 +70,7 @@ function instance($$self, $$props, $$invalidate) {
 	}
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("files" in $$props) $$invalidate(0, files = $$props.files);
 	};
 
diff --git a/test/js/samples/capture-inject-state/expected.js b/test/js/samples/capture-inject-state/expected.js
index cd719ac5d25f..4c058ce87747 100644
--- a/test/js/samples/capture-inject-state/expected.js
+++ b/test/js/samples/capture-inject-state/expected.js
@@ -8,6 +8,7 @@ import {
 	element,
 	init,
 	insert_dev,
+	is_empty,
 	noop,
 	safe_not_equal,
 	set_data_dev,
@@ -119,6 +120,7 @@ function instance($$self, $$props, $$invalidate) {
 	validate_slots("Component", $$slots, []);
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("prop" in $$props) $$subscribe_prop($$invalidate(0, prop = $$props.prop));
 		if ("alias" in $$props) $$invalidate(1, realName = $$props.alias);
 	};
diff --git a/test/js/samples/collapses-text-around-comments/expected.js b/test/js/samples/collapses-text-around-comments/expected.js
index 6fef0f9490d8..6e03a16c06a9 100644
--- a/test/js/samples/collapses-text-around-comments/expected.js
+++ b/test/js/samples/collapses-text-around-comments/expected.js
@@ -7,6 +7,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal,
 	set_data,
@@ -49,6 +50,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { foo = 42 } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("foo" in $$props) $$invalidate(0, foo = $$props.foo);
 	};
 
diff --git a/test/js/samples/computed-collapsed-if/expected.js b/test/js/samples/computed-collapsed-if/expected.js
index 8e5964f8a691..c4acbaf70ec3 100644
--- a/test/js/samples/computed-collapsed-if/expected.js
+++ b/test/js/samples/computed-collapsed-if/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent, init, safe_not_equal } from "svelte/internal";
+import { SvelteComponent, init, is_empty, safe_not_equal } from "svelte/internal";
 
 function instance($$self, $$props, $$invalidate) {
 	let { x } = $$props;
@@ -13,6 +13,7 @@ function instance($$self, $$props, $$invalidate) {
 	}
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("x" in $$props) $$invalidate(0, x = $$props.x);
 	};
 
diff --git a/test/js/samples/data-attribute/expected.js b/test/js/samples/data-attribute/expected.js
index 49ad2f2626ba..0b1a82109472 100644
--- a/test/js/samples/data-attribute/expected.js
+++ b/test/js/samples/data-attribute/expected.js
@@ -6,6 +6,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal,
 	space
@@ -48,6 +49,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { bar } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("bar" in $$props) $$invalidate(0, bar = $$props.bar);
 	};
 
diff --git a/test/js/samples/debug-empty/expected.js b/test/js/samples/debug-empty/expected.js
index dd142adb26b2..4c36e4261b3c 100644
--- a/test/js/samples/debug-empty/expected.js
+++ b/test/js/samples/debug-empty/expected.js
@@ -8,6 +8,7 @@ import {
 	element,
 	init,
 	insert_dev,
+	is_empty,
 	noop,
 	safe_not_equal,
 	set_data_dev,
@@ -80,6 +81,7 @@ function instance($$self, $$props, $$invalidate) {
 	validate_slots("Component", $$slots, []);
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("name" in $$props) $$invalidate(0, name = $$props.name);
 	};
 
diff --git a/test/js/samples/debug-foo-bar-baz-things/expected.js b/test/js/samples/debug-foo-bar-baz-things/expected.js
index 977702b99f5c..27df814ddf50 100644
--- a/test/js/samples/debug-foo-bar-baz-things/expected.js
+++ b/test/js/samples/debug-foo-bar-baz-things/expected.js
@@ -9,6 +9,7 @@ import {
 	element,
 	init,
 	insert_dev,
+	is_empty,
 	noop,
 	safe_not_equal,
 	set_data_dev,
@@ -184,6 +185,7 @@ function instance($$self, $$props, $$invalidate) {
 	validate_slots("Component", $$slots, []);
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("things" in $$props) $$invalidate(0, things = $$props.things);
 		if ("foo" in $$props) $$invalidate(1, foo = $$props.foo);
 		if ("bar" in $$props) $$invalidate(2, bar = $$props.bar);
diff --git a/test/js/samples/debug-foo/expected.js b/test/js/samples/debug-foo/expected.js
index fe62ff77bfb1..bfb988cf8873 100644
--- a/test/js/samples/debug-foo/expected.js
+++ b/test/js/samples/debug-foo/expected.js
@@ -9,6 +9,7 @@ import {
 	element,
 	init,
 	insert_dev,
+	is_empty,
 	noop,
 	safe_not_equal,
 	set_data_dev,
@@ -176,6 +177,7 @@ function instance($$self, $$props, $$invalidate) {
 	validate_slots("Component", $$slots, []);
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("things" in $$props) $$invalidate(0, things = $$props.things);
 		if ("foo" in $$props) $$invalidate(1, foo = $$props.foo);
 	};
diff --git a/test/js/samples/deconflict-builtins/expected.js b/test/js/samples/deconflict-builtins/expected.js
index fb98844ef7a9..dec571fc2fc0 100644
--- a/test/js/samples/deconflict-builtins/expected.js
+++ b/test/js/samples/deconflict-builtins/expected.js
@@ -8,6 +8,7 @@ import {
 	empty,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal,
 	set_data,
@@ -105,6 +106,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { createElement } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("createElement" in $$props) $$invalidate(0, createElement = $$props.createElement);
 	};
 
diff --git a/test/js/samples/deconflict-globals/expected.js b/test/js/samples/deconflict-globals/expected.js
index 7e83c21f0e6e..19ed78f91c14 100644
--- a/test/js/samples/deconflict-globals/expected.js
+++ b/test/js/samples/deconflict-globals/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent, init, safe_not_equal } from "svelte/internal";
+import { SvelteComponent, init, is_empty, safe_not_equal } from "svelte/internal";
 
 import { onMount } from "svelte";
 
@@ -11,6 +11,7 @@ function instance($$self, $$props, $$invalidate) {
 	});
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("foo" in $$props) $$invalidate(0, foo = $$props.foo);
 	};
 
diff --git a/test/js/samples/dev-warning-missing-data-computed/expected.js b/test/js/samples/dev-warning-missing-data-computed/expected.js
index 0a50e2cd970a..8be2957b479e 100644
--- a/test/js/samples/dev-warning-missing-data-computed/expected.js
+++ b/test/js/samples/dev-warning-missing-data-computed/expected.js
@@ -8,6 +8,7 @@ import {
 	element,
 	init,
 	insert_dev,
+	is_empty,
 	noop,
 	safe_not_equal,
 	set_data_dev,
@@ -77,6 +78,7 @@ function instance($$self, $$props, $$invalidate) {
 	validate_slots("Component", $$slots, []);
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("foo" in $$props) $$invalidate(0, foo = $$props.foo);
 	};
 
diff --git a/test/js/samples/each-block-array-literal/expected.js b/test/js/samples/each-block-array-literal/expected.js
index 10d835cf7805..2bd7871e04fe 100644
--- a/test/js/samples/each-block-array-literal/expected.js
+++ b/test/js/samples/each-block-array-literal/expected.js
@@ -8,6 +8,7 @@ import {
 	empty,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal,
 	set_data,
@@ -107,6 +108,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { e } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("a" in $$props) $$invalidate(0, a = $$props.a);
 		if ("b" in $$props) $$invalidate(1, b = $$props.b);
 		if ("c" in $$props) $$invalidate(2, c = $$props.c);
diff --git a/test/js/samples/each-block-changed-check/expected.js b/test/js/samples/each-block-changed-check/expected.js
index f4f9df0de9c1..962ef77f8a2b 100644
--- a/test/js/samples/each-block-changed-check/expected.js
+++ b/test/js/samples/each-block-changed-check/expected.js
@@ -9,6 +9,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal,
 	set_data,
@@ -153,6 +154,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { foo } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("comments" in $$props) $$invalidate(0, comments = $$props.comments);
 		if ("elapsed" in $$props) $$invalidate(1, elapsed = $$props.elapsed);
 		if ("time" in $$props) $$invalidate(2, time = $$props.time);
diff --git a/test/js/samples/each-block-keyed-animated/expected.js b/test/js/samples/each-block-keyed-animated/expected.js
index 7fb81c27a226..6c6b9a3d34cc 100644
--- a/test/js/samples/each-block-keyed-animated/expected.js
+++ b/test/js/samples/each-block-keyed-animated/expected.js
@@ -10,6 +10,7 @@ import {
 	fix_position,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal,
 	set_data,
@@ -129,6 +130,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { things } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("things" in $$props) $$invalidate(0, things = $$props.things);
 	};
 
diff --git a/test/js/samples/each-block-keyed/expected.js b/test/js/samples/each-block-keyed/expected.js
index ad8c074e99f8..5e4b2275d786 100644
--- a/test/js/samples/each-block-keyed/expected.js
+++ b/test/js/samples/each-block-keyed/expected.js
@@ -8,6 +8,7 @@ import {
 	empty,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal,
 	set_data,
@@ -98,6 +99,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { things } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("things" in $$props) $$invalidate(0, things = $$props.things);
 	};
 
diff --git a/test/js/samples/if-block-no-update/expected.js b/test/js/samples/if-block-no-update/expected.js
index f225c221bfe3..ece251084436 100644
--- a/test/js/samples/if-block-no-update/expected.js
+++ b/test/js/samples/if-block-no-update/expected.js
@@ -6,6 +6,7 @@ import {
 	empty,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal
 } from "svelte/internal";
@@ -89,6 +90,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { foo } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("foo" in $$props) $$invalidate(0, foo = $$props.foo);
 	};
 
diff --git a/test/js/samples/if-block-simple/expected.js b/test/js/samples/if-block-simple/expected.js
index eb6c8e89490a..6f4526000b89 100644
--- a/test/js/samples/if-block-simple/expected.js
+++ b/test/js/samples/if-block-simple/expected.js
@@ -6,6 +6,7 @@ import {
 	empty,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal
 } from "svelte/internal";
@@ -67,6 +68,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { foo } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("foo" in $$props) $$invalidate(0, foo = $$props.foo);
 	};
 
diff --git a/test/js/samples/inline-style-optimized-multiple/expected.js b/test/js/samples/inline-style-optimized-multiple/expected.js
index 84a38abd7bbe..bca17c1e3514 100644
--- a/test/js/samples/inline-style-optimized-multiple/expected.js
+++ b/test/js/samples/inline-style-optimized-multiple/expected.js
@@ -5,6 +5,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal,
 	set_style
@@ -45,6 +46,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { y } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("color" in $$props) $$invalidate(0, color = $$props.color);
 		if ("x" in $$props) $$invalidate(1, x = $$props.x);
 		if ("y" in $$props) $$invalidate(2, y = $$props.y);
diff --git a/test/js/samples/inline-style-optimized-url/expected.js b/test/js/samples/inline-style-optimized-url/expected.js
index 77870348a572..38a349017a95 100644
--- a/test/js/samples/inline-style-optimized-url/expected.js
+++ b/test/js/samples/inline-style-optimized-url/expected.js
@@ -5,6 +5,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal,
 	set_style
@@ -38,6 +39,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { data } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("data" in $$props) $$invalidate(0, data = $$props.data);
 	};
 
diff --git a/test/js/samples/inline-style-optimized/expected.js b/test/js/samples/inline-style-optimized/expected.js
index 5bef284f0946..1e136991b150 100644
--- a/test/js/samples/inline-style-optimized/expected.js
+++ b/test/js/samples/inline-style-optimized/expected.js
@@ -5,6 +5,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal,
 	set_style
@@ -38,6 +39,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { color } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("color" in $$props) $$invalidate(0, color = $$props.color);
 	};
 
diff --git a/test/js/samples/inline-style-unoptimized/expected.js b/test/js/samples/inline-style-unoptimized/expected.js
index fdff685eade2..e58a517a2dc9 100644
--- a/test/js/samples/inline-style-unoptimized/expected.js
+++ b/test/js/samples/inline-style-unoptimized/expected.js
@@ -6,6 +6,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal,
 	space
@@ -55,6 +56,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { value } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("style" in $$props) $$invalidate(0, style = $$props.style);
 		if ("key" in $$props) $$invalidate(1, key = $$props.key);
 		if ("value" in $$props) $$invalidate(2, value = $$props.value);
diff --git a/test/js/samples/input-files/expected.js b/test/js/samples/input-files/expected.js
index 0069c2e5f8f8..a653cba16495 100644
--- a/test/js/samples/input-files/expected.js
+++ b/test/js/samples/input-files/expected.js
@@ -6,6 +6,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	listen,
 	noop,
 	safe_not_equal
@@ -50,6 +51,7 @@ function instance($$self, $$props, $$invalidate) {
 	}
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("files" in $$props) $$invalidate(0, files = $$props.files);
 	};
 
diff --git a/test/js/samples/input-range/expected.js b/test/js/samples/input-range/expected.js
index 770baa29ede5..6b29fdd8209d 100644
--- a/test/js/samples/input-range/expected.js
+++ b/test/js/samples/input-range/expected.js
@@ -6,6 +6,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	listen,
 	noop,
 	run_all,
@@ -61,6 +62,7 @@ function instance($$self, $$props, $$invalidate) {
 	}
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("value" in $$props) $$invalidate(0, value = $$props.value);
 	};
 
diff --git a/test/js/samples/input-without-blowback-guard/expected.js b/test/js/samples/input-without-blowback-guard/expected.js
index f19f74dc1ef0..18e75c72bb45 100644
--- a/test/js/samples/input-without-blowback-guard/expected.js
+++ b/test/js/samples/input-without-blowback-guard/expected.js
@@ -6,6 +6,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	listen,
 	noop,
 	safe_not_equal
@@ -54,6 +55,7 @@ function instance($$self, $$props, $$invalidate) {
 	}
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("foo" in $$props) $$invalidate(0, foo = $$props.foo);
 	};
 
diff --git a/test/js/samples/media-bindings/expected.js b/test/js/samples/media-bindings/expected.js
index bcbc0647b84d..16691d675e34 100644
--- a/test/js/samples/media-bindings/expected.js
+++ b/test/js/samples/media-bindings/expected.js
@@ -6,6 +6,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	listen,
 	noop,
 	raf,
@@ -174,6 +175,7 @@ function instance($$self, $$props, $$invalidate) {
 	}
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("buffered" in $$props) $$invalidate(0, buffered = $$props.buffered);
 		if ("seekable" in $$props) $$invalidate(1, seekable = $$props.seekable);
 		if ("played" in $$props) $$invalidate(2, played = $$props.played);
diff --git a/test/js/samples/optional-chaining/expected.js b/test/js/samples/optional-chaining/expected.js
index a28dc129aa0c..fd1f284b5178 100644
--- a/test/js/samples/optional-chaining/expected.js
+++ b/test/js/samples/optional-chaining/expected.js
@@ -8,6 +8,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	mount_component,
 	safe_not_equal,
 	set_data,
@@ -168,6 +169,7 @@ function instance($$self, $$props, $$invalidate) {
 	let Component;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("a" in $$props) $$invalidate(0, a = $$props.a);
 		if ("b" in $$props) $$invalidate(1, b = $$props.b);
 		if ("c" in $$props) $$invalidate(2, c = $$props.c);
diff --git a/test/js/samples/reactive-values-non-topologically-ordered/expected.js b/test/js/samples/reactive-values-non-topologically-ordered/expected.js
index 3d266f10acfb..0689c0ae492a 100644
--- a/test/js/samples/reactive-values-non-topologically-ordered/expected.js
+++ b/test/js/samples/reactive-values-non-topologically-ordered/expected.js
@@ -1,5 +1,5 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent, init, safe_not_equal } from "svelte/internal";
+import { SvelteComponent, init, is_empty, safe_not_equal } from "svelte/internal";
 
 function instance($$self, $$props, $$invalidate) {
 	let { x } = $$props;
@@ -7,6 +7,7 @@ function instance($$self, $$props, $$invalidate) {
 	let b;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("x" in $$props) $$invalidate(0, x = $$props.x);
 	};
 
diff --git a/test/js/samples/reactive-values-non-writable-dependencies/expected.js b/test/js/samples/reactive-values-non-writable-dependencies/expected.js
index 38bd356d85e4..69737b71bd38 100644
--- a/test/js/samples/reactive-values-non-writable-dependencies/expected.js
+++ b/test/js/samples/reactive-values-non-writable-dependencies/expected.js
@@ -1,11 +1,12 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent, init, safe_not_equal } from "svelte/internal";
+import { SvelteComponent, init, is_empty, safe_not_equal } from "svelte/internal";
 
 function instance($$self, $$props, $$invalidate) {
 	let { a = 1 } = $$props;
 	let { b = 2 } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("a" in $$props) $$invalidate(0, a = $$props.a);
 		if ("b" in $$props) $$invalidate(1, b = $$props.b);
 	};
diff --git a/test/js/samples/select-dynamic-value/expected.js b/test/js/samples/select-dynamic-value/expected.js
index aa4e5004fdfe..d53dd6de5bf9 100644
--- a/test/js/samples/select-dynamic-value/expected.js
+++ b/test/js/samples/select-dynamic-value/expected.js
@@ -6,6 +6,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal,
 	select_option
@@ -51,6 +52,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { current } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("current" in $$props) $$invalidate(0, current = $$props.current);
 	};
 
diff --git a/test/js/samples/src-attribute-check/expected.js b/test/js/samples/src-attribute-check/expected.js
index e03b3a6ba7ee..2516b884d334 100644
--- a/test/js/samples/src-attribute-check/expected.js
+++ b/test/js/samples/src-attribute-check/expected.js
@@ -8,6 +8,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal,
 	space
@@ -68,6 +69,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { slug } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("url" in $$props) $$invalidate(0, url = $$props.url);
 		if ("slug" in $$props) $$invalidate(1, slug = $$props.slug);
 	};
diff --git a/test/js/samples/title/expected.js b/test/js/samples/title/expected.js
index d4e7e1a58491..9e9e1a11dc39 100644
--- a/test/js/samples/title/expected.js
+++ b/test/js/samples/title/expected.js
@@ -1,5 +1,11 @@
 /* generated by Svelte vX.Y.Z */
-import { SvelteComponent, init, noop, safe_not_equal } from "svelte/internal";
+import {
+	SvelteComponent,
+	init,
+	is_empty,
+	noop,
+	safe_not_equal
+} from "svelte/internal";
 
 function create_fragment(ctx) {
 	let title_value;
@@ -23,6 +29,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { custom } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("custom" in $$props) $$invalidate(0, custom = $$props.custom);
 	};
 
diff --git a/test/js/samples/transition-local/expected.js b/test/js/samples/transition-local/expected.js
index 25a03f026f75..dacdff7266d8 100644
--- a/test/js/samples/transition-local/expected.js
+++ b/test/js/samples/transition-local/expected.js
@@ -8,6 +8,7 @@ import {
 	empty,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal,
 	transition_in
@@ -125,6 +126,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { y } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("x" in $$props) $$invalidate(0, x = $$props.x);
 		if ("y" in $$props) $$invalidate(1, y = $$props.y);
 	};
diff --git a/test/js/samples/transition-repeated-outro/expected.js b/test/js/samples/transition-repeated-outro/expected.js
index 1f76a93666be..8ce7aec4f40c 100644
--- a/test/js/samples/transition-repeated-outro/expected.js
+++ b/test/js/samples/transition-repeated-outro/expected.js
@@ -9,6 +9,7 @@ import {
 	group_outros,
 	init,
 	insert,
+	is_empty,
 	safe_not_equal,
 	transition_in,
 	transition_out
@@ -103,6 +104,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { num = 1 } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("num" in $$props) $$invalidate(0, num = $$props.num);
 	};
 
diff --git a/test/js/samples/use-elements-as-anchors/expected.js b/test/js/samples/use-elements-as-anchors/expected.js
index 5be8808edbcf..359d82702c9a 100644
--- a/test/js/samples/use-elements-as-anchors/expected.js
+++ b/test/js/samples/use-elements-as-anchors/expected.js
@@ -7,6 +7,7 @@ import {
 	empty,
 	init,
 	insert,
+	is_empty,
 	noop,
 	safe_not_equal,
 	space
@@ -244,6 +245,7 @@ function instance($$self, $$props, $$invalidate) {
 	let { e } = $$props;
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("a" in $$props) $$invalidate(0, a = $$props.a);
 		if ("b" in $$props) $$invalidate(1, b = $$props.b);
 		if ("c" in $$props) $$invalidate(2, c = $$props.c);
diff --git a/test/js/samples/video-bindings/expected.js b/test/js/samples/video-bindings/expected.js
index d3920ef8c287..10a96a7a3e7d 100644
--- a/test/js/samples/video-bindings/expected.js
+++ b/test/js/samples/video-bindings/expected.js
@@ -7,6 +7,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	listen,
 	noop,
 	raf,
@@ -94,6 +95,7 @@ function instance($$self, $$props, $$invalidate) {
 	}
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("currentTime" in $$props) $$invalidate(0, currentTime = $$props.currentTime);
 		if ("videoHeight" in $$props) $$invalidate(1, videoHeight = $$props.videoHeight);
 		if ("videoWidth" in $$props) $$invalidate(2, videoWidth = $$props.videoWidth);
diff --git a/test/js/samples/window-binding-scroll/expected.js b/test/js/samples/window-binding-scroll/expected.js
index 45d992c72161..8844b92ad0df 100644
--- a/test/js/samples/window-binding-scroll/expected.js
+++ b/test/js/samples/window-binding-scroll/expected.js
@@ -7,6 +7,7 @@ import {
 	element,
 	init,
 	insert,
+	is_empty,
 	listen,
 	noop,
 	safe_not_equal,
@@ -79,6 +80,7 @@ function instance($$self, $$props, $$invalidate) {
 	}
 
 	$$self.$set = $$props => {
+		if (is_empty($$props)) return;
 		if ("y" in $$props) $$invalidate(0, y = $$props.y);
 	};