feat allow multiple elements assigned with same slot

src/compiler/compile/render_dom/wrappers/Element/index.ts

@@ -205,6 +205,14 @@ export default class ElementWrapper extends Wrapper {
 							get_slot_definition(child_block, scope, lets)
 						);
 						this.renderer.blocks.push(child_block);
+					} else {
+						const { lets } = this.node;
+						const seen = new Set(lets.map(l => l.name.name));
+
+						(owner as InlineComponentWrapper).node.lets.forEach(l => {
+							if (!seen.has(l.name.name)) lets.push(l);
+						});
+						(owner as InlineComponentWrapper).slots.get(name).add_let_binding(lets);
 					}
 
 					this.slot_block = (owner as unknown as InlineComponentWrapper).slots.get(name).block;

src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts

@@ -9,9 +9,8 @@ import { b, x, p } from 'code-red';
 import Attribute from '../../../nodes/Attribute';
 import get_object from '../../../utils/get_object';
 import create_debugging_comment from '../shared/create_debugging_comment';
-import { get_slot_definition } from '../shared/get_slot_definition';
+import { get_slot_definition, SlotDefinition } from '../shared/get_slot_definition';
 import EachBlock from '../../../nodes/EachBlock';
-import TemplateScope from '../../../nodes/shared/TemplateScope';
 import is_dynamic from '../shared/is_dynamic';
 import bind_this from '../shared/bind_this';
 import { Node, Identifier, ObjectExpression } from 'estree';
@@ -20,7 +19,7 @@ import { extract_names } from 'periscopic';
 
 export default class InlineComponentWrapper extends Wrapper {
 	var: Identifier;
-	slots: Map<string, { block: Block; scope: TemplateScope; get_context?: Node; get_changes?: Node }> = new Map();
+	slots: Map<string, SlotDefinition> = new Map();
 	node: InlineComponent;
 	fragment: FragmentWrapper;
 
@@ -130,7 +129,7 @@ export default class InlineComponentWrapper extends Wrapper {
 			? [
 				p`$$slots: {
 					${Array.from(this.slots).map(([name, slot]) => {
-						return p`${name}: [${slot.block.name}, ${slot.get_context || null}, ${slot.get_changes || null}]`;
+						return p`${name}: ${slot.render()}`;
 					})}
 				}`,
 				p`$$scope: {

src/compiler/compile/render_dom/wrappers/shared/get_slot_definition.ts

@@ -4,78 +4,112 @@ import Block from '../../Block';
 import TemplateScope from '../../../nodes/shared/TemplateScope';
 import { BinaryExpression } from 'estree';
 
-export function get_slot_definition(block: Block, scope: TemplateScope, lets: Let[]) {
-	if (lets.length === 0) return { block, scope };
-
-	const input = {
-		type: 'ObjectPattern',
-		properties: lets.map(l => ({
-			type: 'Property',
-			kind: 'init',
-			key: l.name,
-			value: l.value || l.name
-		}))
-	};
-
-	const names: Set<string> = new Set();
-	lets.forEach(l => {
-		l.names.forEach(name => {
-			names.add(name);
-		});
-	});
-
-	const context = {
-		type: 'ObjectExpression',
-		properties: Array.from(names).map(name => p`${block.renderer.context_lookup.get(name).index}: ${name}`)
-	};
-
-	const { context_lookup } = block.renderer;
-
-	// i am well aware that this code is gross
-	// TODO make it less gross
-	const changes = {
-		type: 'ParenthesizedExpression',
-		get expression() {
-			if (block.renderer.context_overflow) {
-				const grouped = [];
-
-				Array.from(names).forEach(name => {
-					const i = context_lookup.get(name).index.value as number;
-					const g = Math.floor(i / 31);
-
-					if (!grouped[g]) grouped[g] = [];
-					grouped[g].push({ name, n: i % 31 });
-				});
-
-				const elements = [];
-
-				for (let g = 0; g < grouped.length; g += 1) {
-					elements[g] = grouped[g]
-						? grouped[g]
-							.map(({ name, n }) => x`${name} ? ${1 << n} : 0`)
-							.reduce((lhs, rhs) => x`${lhs} | ${rhs}`)
-						: x`0`;
-				}
+export function get_slot_definition(
+	block: Block,
+	scope: TemplateScope,
+	lets: Let[]
+) {
+	return new SlotDefinition(block, scope, lets);
+}
+
+export class SlotDefinition {
+	block: Block;
+	scope: TemplateScope;
+	lets: Let[];
+	lets_set: Set<string>;
+
+	constructor(block: Block, scope: TemplateScope, lets: Let[]) {
+		this.block = block;
+		this.scope = scope;
+		this.lets = lets;
+		this.lets_set = new Set(this.lets.map(l => l.name.name));
+	}
 
-				return {
-					type: 'ArrayExpression',
-					elements
-				};
+	add_let_binding(lets: Let[]) {
+		for (const l of lets) {
+			if (!this.lets_set.has(l.name.name)) {
+				this.lets_set.add(l.name.name);
+				this.lets.push(l);
 			}
+		}
+	}
 
-			return Array.from(names)
-				.map(name => {
-					const i = context_lookup.get(name).index.value as number;
-					return x`${name} ? ${1 << i} : 0`;
-				})
-				.reduce((lhs, rhs) => x`${lhs} | ${rhs}`) as BinaryExpression;
+	render() {
+		if (this.lets.length === 0) {
+			return x`[${this.block.name}, null, null]`;
 		}
-	};
-
-	return {
-		block,
-		scope,
-		get_context: x`${input} => ${context}`,
-		get_changes: x`${input} => ${changes}`
-	};
+
+		const input = {
+			type: 'ObjectPattern',
+			properties: this.lets.map(l => ({
+				type: 'Property',
+				kind: 'init',
+				key: l.name,
+				value: l.value || l.name,
+			})),
+		};
+
+		const names: Set<string> = new Set();
+		this.lets.forEach(l => {
+			l.names.forEach(name => {
+				names.add(name);
+			});
+		});
+
+		const context = {
+			type: 'ObjectExpression',
+			properties: Array.from(names).map(
+				name =>
+					p`${this.block.renderer.context_lookup.get(name).index}: ${name}`
+			),
+		};
+
+		const { context_lookup } = this.block.renderer;
+		const { renderer } = this.block;
+
+		// i am well aware that this code is gross
+		// TODO make it less gross
+		const changes = {
+			type: 'ParenthesizedExpression',
+			get expression() {
+				if (renderer.context_overflow) {
+					const grouped = [];
+					Array.from(names).forEach(name => {
+						const i = context_lookup.get(name).index.value as number;
+						const g = Math.floor(i / 31);
+
+						if (!grouped[g]) grouped[g] = [];
+						grouped[g].push({ name, n: i % 31 });
+					});
+
+					const elements = [];
+
+					for (let g = 0; g < grouped.length; g += 1) {
+						elements[g] = grouped[g]
+							? grouped[g]
+									.map(({ name, n }) => x`${name} ? ${1 << n} : 0`)
+									.reduce((lhs, rhs) => x`${lhs} | ${rhs}`)
+							: x`0`;
+					}
+
+					return {
+						type: 'ArrayExpression',
+						elements,
+					};
+				}
+
+				return Array.from(names)
+					.map(name => {
+						const i = context_lookup.get(name).index.value as number;
+						return x`${name} ? ${1 << i} : 0`;
+					})
+					.reduce((lhs, rhs) => x`${lhs} | ${rhs}`) as BinaryExpression;
+			},
+		};
+
+		const get_context = x`${input} => ${context}`;
+		const get_changes = x`${input} => ${changes}`;
+
+		return x`[${this.block.name}, ${get_context}, ${get_changes}]`;
+	}
 }

src/compiler/compile/render_ssr/handlers/Element.ts

@@ -1,14 +1,14 @@
 import { is_void } from '../../../utils/names';
 import { get_attribute_value, get_class_attribute_value } from './shared/get_attribute_value';
-import { get_slot_scope } from './shared/get_slot_scope';
 import { boolean_attributes } from './shared/boolean_attributes';
 import Renderer, { RenderOptions } from '../Renderer';
 import Element from '../../nodes/Element';
 import { x } from 'code-red';
 import Expression from '../../nodes/shared/Expression';
+import { SlotDefinition } from './shared/get_slot_definition';
 
 export default function(node: Element, renderer: Renderer, options: RenderOptions & {
-	slot_scopes: Map<any, any>;
+	slot_scopes: Map<string, SlotDefinition>;
 }) {
 	// awkward special case
 	let node_contents;
@@ -154,10 +154,11 @@ export default function(node: Element, renderer: Renderer, options: RenderOption
 			if (!seen.has(l.name.name)) lets.push(l);
 		});
 
-		options.slot_scopes.set(slot, {
-			input: get_slot_scope(node.lets),
-			output: renderer.pop()
-		});
+		if (options.slot_scopes.has(slot as string)) {
+			options.slot_scopes.get(slot as string).add(node.lets, renderer.pop());
+		} else {
+			options.slot_scopes.set(slot as string, new SlotDefinition(node.lets, renderer.pop()));
+		}
 	} else {
 		renderer.render(node.children, options);
 

src/compiler/compile/render_ssr/handlers/InlineComponent.ts

@@ -1,8 +1,8 @@
 import { string_literal } from '../../utils/stringify';
 import Renderer, { RenderOptions } from '../Renderer';
-import { get_slot_scope } from './shared/get_slot_scope';
 import InlineComponent from '../../nodes/InlineComponent';
 import { p, x } from 'code-red';
+import { SlotDefinition } from './shared/get_slot_definition';
 
 function get_prop_value(attribute) {
 	if (attribute.is_true) return x`true`;
@@ -68,7 +68,7 @@ export default function(node: InlineComponent, renderer: Renderer, options: Rend
 	const slot_fns = [];
 
 	if (node.children.length) {
-		const slot_scopes = new Map();
+		const slot_scopes: Map<string, SlotDefinition> = new Map();
 
 		renderer.push();
 
@@ -76,14 +76,11 @@ export default function(node: InlineComponent, renderer: Renderer, options: Rend
 			slot_scopes
 		}));
 
-		slot_scopes.set('default', {
-			input: get_slot_scope(node.lets),
-			output: renderer.pop()
-		});
+		slot_scopes.set('default', new SlotDefinition(node.lets, renderer.pop()));
 
-		slot_scopes.forEach(({ input, output }, name) => {
+		slot_scopes.forEach((slot, name) => {
 			slot_fns.push(
-				p`${name}: (${input}) => ${output}`
+				p`${name}: ${slot.render()}`
 			);
 		});
 	}

src/compiler/compile/render_ssr/handlers/shared/get_slot_definition.ts

@@ -0,0 +1,59 @@
+import Let from '../../../nodes/Let';
+import { TemplateLiteral } from 'estree';
+import { x } from 'code-red';
+import { get_slot_scope } from './get_slot_scope';
+
+export function get_slot_definition(
+	lets: Let[],
+	output_template: TemplateLiteral
+) {
+	return new SlotDefinition(lets, output_template);
+}
+
+export class SlotDefinition {
+	lets: Let[];
+	lets_set: Set<string>;
+	output_template: TemplateLiteral;
+
+	constructor(lets: Let[], output_template: TemplateLiteral) {
+		this.lets = lets;
+		this.output_template = output_template;
+		this.lets_set = new Set(this.lets.map(l => l.name.name));
+	}
+
+	add(lets: Let[], output_template: TemplateLiteral) {
+		for (const l of lets) {
+			if (!this.lets_set.has(l.name.name)) {
+				this.lets_set.add(l.name.name);
+				this.lets.push(l);
+			}
+		}
+		this.output_template = merge_template_literal(
+			this.output_template,
+			output_template
+		);
+	}
+
+	render() {
+    return x`(${get_slot_scope(this.lets)}) => ${this.output_template}`;
+  }
+}
+
+function merge_template_literal(a: TemplateLiteral, b: TemplateLiteral): TemplateLiteral {
+	const quasis = [...a.quasis];
+	quasis[quasis.length - 1] = {
+		type: 'TemplateElement',
+		value: {
+			raw: quasis[quasis.length - 1].value.raw + b.quasis[0].value.raw,
+			cooked: quasis[quasis.length - 1].value.cooked + b.quasis[0].value.cooked,
+		},
+		tail: false,
+	};
+	quasis.push(...b.quasis.slice(1));
+
+	return {
+		type: 'TemplateLiteral',
+		quasis,
+		expressions: [...a.expressions, ...b.expressions],
+	};
+}

test/runtime/samples/component-slot-let-multiple-slot/Nested.svelte

@@ -0,0 +1,6 @@
+<script>
+	let a = "A", b = "B", x = "X";
+</script>
+
+<slot name="a" {x} {a}></slot>
+<slot name="b" {x} {b}></slot>

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

@@ -0,0 +1,8 @@
+export default {
+	html: `
+		<p slot="a">A X</p>
+		<p slot="a">X</p>
+		<p slot="b">X</p>
+		<p slot="b">B X</p>
+	`,
+};

test/runtime/samples/component-slot-let-multiple-slot/main.svelte

@@ -0,0 +1,11 @@
+<script>
+	import Nested from './Nested.svelte';
+</script>
+
+<Nested let:x>
+	<p slot="a" let:a>{a} {x}</p>
+	<p slot="a">{x}</p>
+
+	<p slot="b">{x}</p>
+	<p slot="b" let:b>{b} {x}</p>
+</Nested>