more gnarly slot stuff

src/compile/render-dom/wrappers/Slot.ts

@@ -6,6 +6,9 @@ import FragmentWrapper from './Fragment';
 import deindent from '../../../utils/deindent';
 import sanitize from '../../../utils/sanitize';
 import addToSet from '../../../utils/addToSet';
+import get_slot_data from '../../../utils/get_slot_data';
+import stringifyProps from '../../../utils/stringifyProps';
+import Expression from '../../nodes/shared/Expression';
 
 export default class SlotWrapper extends Wrapper {
 	node: Slot;
@@ -51,11 +54,50 @@ export default class SlotWrapper extends Wrapper {
 		const slot_name = this.node.getStaticAttributeValue('name') || 'default';
 		renderer.slots.add(slot_name);
 
+		let get_slot_changes;
+		let get_slot_context;
+
+		const attributes = this.node.attributes.filter(attribute => attribute.name !== 'name');
+
+		if (attributes.length > 0) {
+			get_slot_changes = renderer.component.getUniqueName(`get_${slot_name}_slot_changes`);
+			get_slot_context = renderer.component.getUniqueName(`get_${slot_name}_slot_context`);
+
+			const context_props = get_slot_data(attributes);
+			const changes_props = [];
+
+			const dependencies = new Set();
+
+			attributes.forEach(attribute => {
+				attribute.chunks.forEach(chunk => {
+					if ((<Expression>chunk).dependencies) {
+						addToSet(dependencies, (<Expression>chunk).dependencies);
+						addToSet(dependencies, (<Expression>chunk).contextual_dependencies);
+					}
+				});
+
+				if (attribute.dependencies.size > 0) {
+					changes_props.push(`${attribute.name}: ${[...attribute.dependencies].join(' || ')}`)
+				}
+			});
+
+			const arg = dependencies.size > 0 ? `{ ${[...dependencies].join(', ')} }` : '{}';
+
+			renderer.blocks.push(deindent`
+				const ${get_slot_changes} = (${arg}) => (${stringifyProps(changes_props)});
+				const ${get_slot_context} = (${arg}) => (${stringifyProps(context_props)});
+			`);
+		} else {
+			get_slot_context = 'null';
+		}
+
 		const slot = block.getUniqueName(`${sanitize(slot_name)}_slot`);
+		const slot_definition = block.getUniqueName(`${sanitize(slot_name)}_slot`);
 
-		block.builders.init.addLine(
-			`const ${slot} = @create_slot(ctx.$$slot_${sanitize(slot_name)}, ctx);`
-		);
+		block.builders.init.addBlock(deindent`
+			const ${slot_definition} = ctx.$$slot_${sanitize(slot_name)};
+			const ${slot} = @create_slot(${slot_definition}, ctx, ${get_slot_context});
+		`);
 
 		let mountBefore = block.builders.mount.toString();
 
@@ -100,7 +142,7 @@ export default class SlotWrapper extends Wrapper {
 
 		block.builders.update.addBlock(deindent`
 			if (${slot} && ${update_conditions}) {
-				${slot}.p(@assign(@assign({}, changed), ctx.$$scope.changed), @get_slot_context(ctx.$$slot_${sanitize(slot_name)}, ctx));
+				${slot}.p(@assign(@assign({}, ${get_slot_changes}(changed)), ctx.$$scope.changed), @get_slot_context(${slot_definition}, ctx, ${get_slot_context}));
 			}
 		`);
 

src/compile/render-ssr/handlers/AwaitBlock.ts

@@ -1,6 +1,6 @@
 import Renderer from '../Renderer';
 import { CompileOptions } from '../../../interfaces';
-import { snip } from '../utils';
+import { snip } from '../../../utils/snip';
 
 export default function(node, renderer: Renderer, options: CompileOptions) {
 	renderer.append('${(function(__value) { if(@isPromise(__value)) return `');

src/compile/render-ssr/handlers/EachBlock.ts

@@ -1,4 +1,4 @@
-import { snip } from '../utils';
+import { snip } from '../../../utils/snip';
 
 export default function(node, renderer, options) {
 	const snippet = snip(node.expression);

src/compile/render-ssr/handlers/Element.ts

@@ -2,8 +2,8 @@ import { quotePropIfNecessary, quoteNameIfNecessary } from '../../../utils/quote
 import isVoidElementName from '../../../utils/isVoidElementName';
 import Attribute from '../../nodes/Attribute';
 import Node from '../../nodes/shared/Node';
-import { snip } from '../utils';
-import { stringify_attribute } from './shared/stringify_attribute';
+import { snip } from '../../../utils/snip';
+import { stringify_attribute } from '../../../utils/stringify_attribute';
 import { get_slot_scope } from './shared/get_slot_scope';
 
 // source: https://gist.github.com/ArjanSchouten/0b8574a6ad7f5065a5e7

src/compile/render-ssr/handlers/HtmlTag.ts

@@ -1,4 +1,4 @@
-import { snip } from '../utils';
+import { snip } from '../../../utils/snip';
 
 export default function(node, renderer, options) {
 	renderer.append('${' + snip(node.expression) + '}');

src/compile/render-ssr/handlers/IfBlock.ts

@@ -1,4 +1,4 @@
-import { snip } from '../utils';
+import { snip } from '../../../utils/snip';
 
 export default function(node, renderer, options) {
 	const snippet = snip(node.expression);

src/compile/render-ssr/handlers/InlineComponent.ts

@@ -1,6 +1,6 @@
 import { escape, escapeTemplate, stringify } from '../../../utils/stringify';
 import { quoteNameIfNecessary } from '../../../utils/quoteIfNecessary';
-import { snip } from '../utils';
+import { snip } from '../../../utils/snip';
 import Renderer from '../Renderer';
 import stringifyProps from '../../../utils/stringifyProps';
 import { get_slot_scope } from './shared/get_slot_scope';

src/compile/render-ssr/handlers/Slot.ts

@@ -1,6 +1,5 @@
 import { quotePropIfNecessary } from '../../../utils/quoteIfNecessary';
-import { snip } from '../utils';
-import { stringify_attribute } from './shared/stringify_attribute';
+import get_slot_data from '../../../utils/get_slot_data';
 
 export default function(node, renderer, options) {
 	const name = node.attributes.find(attribute => attribute.name === 'name');
@@ -8,21 +7,9 @@ export default function(node, renderer, options) {
 	const slot_name = name && name.chunks[0].data || 'default';
 	const prop = quotePropIfNecessary(slot_name);
 
-	const slot_data = node.attributes
-		.filter(attribute => attribute.name !== 'name')
-		.map(attribute => {
-			const value = attribute.isTrue
-				? 'true'
-				: attribute.chunks.length === 0
-					? '""'
-					: attribute.chunks.length === 1 && attribute.chunks[0].type !== 'Text'
-						? snip(attribute.chunks[0])
-						: stringify_attribute(attribute);
+	const slot_data = get_slot_data(node.attributes);
 
-			return `${attribute.name}: ${value}`;
-		});
-
-	const arg = slot_data ? `{ ${slot_data.join(', ')} }` : '';
+	const arg = slot_data.length > 0 ? `{ ${slot_data.join(', ')} }` : '';
 
 	renderer.append(`\${$$slots${prop} ? $$slots${prop}(${arg}) : \``);
 

src/compile/render-ssr/handlers/Tag.ts

@@ -1,4 +1,4 @@
-import { snip } from '../utils';
+import { snip } from '../../../utils/snip';
 
 export default function(node, renderer, options) {
 	const snippet = snip(node.expression);

src/internal/utils.js

@@ -47,16 +47,16 @@ export function validate_store(store, name) {
 	}
 }
 
-export function create_slot(definition, ctx) {
+export function create_slot(definition, ctx, fn) {
 	if (definition) {
-		const slot_ctx = get_slot_context(definition, ctx);
+		const slot_ctx = get_slot_context(definition, ctx, fn);
 		return definition[0](slot_ctx);
 	}
 }
 
-export function get_slot_context(definition, ctx) {
+export function get_slot_context(definition, ctx, fn) {
 	return definition[1]
-		? assign({}, assign(ctx.$$scope.ctx, definition[1](ctx)))
-		: ctx.$$scope.ctx
+		? assign({}, assign(ctx.$$scope.ctx, definition[1](fn ? fn(ctx) : {})))
+		: ctx.$$scope.ctx;
 }
 

src/utils/get_slot_data.ts

@@ -0,0 +1,18 @@
+import { snip } from './snip';
+import { stringify_attribute } from './stringify_attribute';
+
+export default function(attributes) {
+	return attributes
+		.filter(attribute => attribute.name !== 'name')
+		.map(attribute => {
+			const value = attribute.isTrue
+				? 'true'
+				: attribute.chunks.length === 0
+					? '""'
+					: attribute.chunks.length === 1 && attribute.chunks[0].type !== 'Text'
+						? snip(attribute.chunks[0])
+						: stringify_attribute(attribute);
+
+			return `${attribute.name}: ${value}`;
+		});
+}

src/utils/stringify_attribute.ts

@@ -1,7 +1,7 @@
-import Attribute from '../../../nodes/Attribute';
-import Node from '../../../nodes/shared/Node';
-import { escapeTemplate, escape } from '../../../../utils/stringify';
-import { snip } from '../../utils';
+import Attribute from '../compile/nodes/Attribute';
+import Node from '../compile/nodes/shared/Node';
+import { escapeTemplate, escape } from './stringify';
+import { snip } from './snip';
 
 export function stringify_attribute(attribute: Attribute) {
 	return attribute.chunks

test/runtime/samples/component-slot-let-c/Nested.html

@@ -0,0 +1,6 @@
+<script>
+	let count = 0;
+</script>
+
+<button on:click="{() => count += 1}">+1</button>
+<slot c={count}/>

test/runtime/samples/component-slot-let-c/_config.js

@@ -0,0 +1,18 @@
+export default {
+	html: `
+		<button>+1</button>
+		<span>0 (undefined)</span>
+	`,
+
+	async test({ assert, target, window }) {
+		const button = target.querySelector('button');
+		const click = new window.MouseEvent('click');
+
+		await button.dispatchEvent(click);
+
+		assert.htmlEqual(target.innerHTML, `
+			<button>+1</button>
+			<span>1 (undefined)</span>
+		`);
+	}
+};

test/runtime/samples/component-slot-let-c/main.html

@@ -0,0 +1,7 @@
+<script>
+	import Nested from './Nested.html';
+</script>
+
+<Nested let:c let:count>
+	<span>{c} ({count})</span>
+</Nested>