capture local variables in $capture_state

src/compiler/compile/render_dom/index.ts

@@ -1,7 +1,7 @@
 import { b, x, p } from 'code-red';
 import Component from '../Component';
 import Renderer from './Renderer';
-import { CompileOptions } from '../../interfaces';
+import { CompileOptions, Var } from '../../interfaces';
 import { walk } from 'estree-walker';
 import add_to_set from '../utils/add_to_set';
 import { extract_names } from '../utils/scope';
@@ -167,27 +167,41 @@ export default function dom(
 			`;
 		}
 
-		capture_state = (uses_props || writable_props.length > 0) ? x`
-			() => {
-				return { ${component.vars.filter(prop => prop.writable).map(prop => p`${prop.name}`)} };
-			}
-		` : x`
-			() => {
-				return {};
-			}
-		`;
+		// we need to filter out store subscriptions ($x) or $inject_state will try to call .set() on them, leading
+		// to a crash if store is not writable (and probably not intended behaviour to change store value)
+		const is_not_sub = (variable: Var) => variable.name.substr(0, 1) !== '$';
 
-		const writable_vars = component.vars.filter(variable => !variable.module && variable.writable);
-		inject_state = (uses_props || writable_vars.length > 0) ? x`
-			${$$props} => {
-				${uses_props && component.invalidate('$$props', x`$$props = @assign(@assign({}, $$props), $$new_props)`)}
-				${writable_vars.map(prop => b`
-					if ('${prop.name}' in $$props) ${component.invalidate(prop.name, x`${prop.name} = ${$$props}.${prop.name}`)};
-				`)}
-			}
-		` : x`
-			${$$props} => {}
-		`;
+		const capturable_vars = component.vars.filter(
+			variable => !variable.module && variable.writable && is_not_sub(variable)
+		);
+
+		if (uses_props || capturable_vars.length > 0) {
+
+			const capturable_props = writable_props.filter(is_not_sub);
+
+			const local_vars = capturable_vars.filter(variable => !variable.export_name);
+
+			const var_names = (variables: Var[]) => variables.map(prop => p`${prop.name}`);
+
+			capture_state = x`
+				({ props: $props = true, local: $local = true } = {}) => ({
+					...${x`$props && { ${var_names(capturable_props)} }`},
+					...${x`$local && { ${var_names(local_vars)} }`}
+				})
+			`;
+
+			inject_state = x`
+				${$$props} => {
+					${uses_props && component.invalidate('$$props', x`$$props = @assign(@assign({}, $$props), $$new_props)`)}
+					${capturable_vars.map(prop => b`
+						if ('${prop.name}' in $$props) ${component.invalidate(prop.name, x`${prop.name} = ${$$props}.${prop.name}`)};
+					`)}
+				}
+			`;
+		} else {
+			capture_state = x`() => ({})`;
+			inject_state = x`() => {}`;
+		}
 	}
 
 	// instrument assignments

test/js/samples/debug-empty/expected.js

@@ -78,9 +78,10 @@ function instance($$self, $$props, $$invalidate) {
 		if ("name" in $$props) $$invalidate("name", name = $$props.name);
 	};
 
-	$$self.$capture_state = () => {
-		return { name };
-	};
+	$$self.$capture_state = ({ props: $props = true, local: $local = true } = {}) => ({
+		...$props && ({ name }),
+		...$local && ({})
+	});
 
 	$$self.$inject_state = $$props => {
 		if ("name" in $$props) $$invalidate("name", name = $$props.name);
@@ -118,4 +119,4 @@ class Component extends SvelteComponentDev {
 	}
 }
 
-export default Component;
+export default Component;

test/js/samples/debug-foo-bar-baz-things/expected.js

@@ -175,9 +175,10 @@ function instance($$self, $$props, $$invalidate) {
 		if ("baz" in $$props) $$invalidate("baz", baz = $$props.baz);
 	};
 
-	$$self.$capture_state = () => {
-		return { things, foo, bar, baz };
-	};
+	$$self.$capture_state = ({ props: $props = true, local: $local = true } = {}) => ({
+		...$props && ({ things, foo, bar, baz }),
+		...$local && ({})
+	});
 
 	$$self.$inject_state = $$props => {
 		if ("things" in $$props) $$invalidate("things", things = $$props.things);
@@ -254,4 +255,4 @@ class Component extends SvelteComponentDev {
 	}
 }
 
-export default Component;
+export default Component;

test/js/samples/debug-foo/expected.js

@@ -171,9 +171,10 @@ function instance($$self, $$props, $$invalidate) {
 		if ("foo" in $$props) $$invalidate("foo", foo = $$props.foo);
 	};
 
-	$$self.$capture_state = () => {
-		return { things, foo };
-	};
+	$$self.$capture_state = ({ props: $props = true, local: $local = true } = {}) => ({
+		...$props && ({ things, foo }),
+		...$local && ({})
+	});
 
 	$$self.$inject_state = $$props => {
 		if ("things" in $$props) $$invalidate("things", things = $$props.things);
@@ -224,4 +225,4 @@ class Component extends SvelteComponentDev {
 	}
 }
 
-export default Component;
+export default Component;

test/js/samples/debug-hoisted/expected.js

@@ -49,9 +49,10 @@ let kobzol = 5;
 function instance($$self) {
 	let obj = { x: 5 };
 
-	$$self.$capture_state = () => {
-		return {};
-	};
+	$$self.$capture_state = ({ props: $props = true, local: $local = true } = {}) => ({
+		...$props && ({}),
+		...$local && ({ obj, kobzol })
+	});
 
 	$$self.$inject_state = $$props => {
 		if ("obj" in $$props) $$invalidate("obj", obj = $$props.obj);
@@ -75,4 +76,4 @@ class Component extends SvelteComponentDev {
 	}
 }
 
-export default Component;
+export default Component;

test/js/samples/dev-warning-missing-data-computed/expected.js

@@ -75,9 +75,10 @@ function instance($$self, $$props, $$invalidate) {
 		if ("foo" in $$props) $$invalidate("foo", foo = $$props.foo);
 	};
 
-	$$self.$capture_state = () => {
-		return { foo, bar };
-	};
+	$$self.$capture_state = ({ props: $props = true, local: $local = true } = {}) => ({
+		...$props && ({ foo }),
+		...$local && ({ bar })
+	});
 
 	$$self.$inject_state = $$props => {
 		if ("foo" in $$props) $$invalidate("foo", foo = $$props.foo);
@@ -122,4 +123,4 @@ class Component extends SvelteComponentDev {
 	}
 }
 
-export default Component;
+export default Component;