support else for each block too

fix lint errors

src/compiler/compile/render_dom/wrappers/EachBlock.ts

@@ -27,6 +27,7 @@ export class ElseBlockWrapper extends Wrapper {
 		next_sibling: Wrapper
 	) {
 		super(renderer, block, parent, node);
+		add_const_tags_context(renderer, this.node.const_tags);
 
 		this.block = block.child({
 			comment: create_debugging_comment(node, this.renderer.component),
@@ -257,6 +258,18 @@ export default class EachBlockWrapper extends Wrapper {
 		}
 
 		if (this.else) {
+			let else_ctx = x`#ctx`;
+			if (this.else.node.const_tags.length > 0) {
+				const get_ctx_name = this.renderer.component.get_unique_name('get_else_ctx');
+				this.renderer.blocks.push(b`
+					function ${get_ctx_name}(#ctx) {
+						const child_ctx = #ctx.slice();
+						${add_const_tags(block, this.else.node.const_tags, 'child_ctx')}
+						return child_ctx;
+					}
+				`);
+				else_ctx = x`${get_ctx_name}(#ctx)`;
+			}
 			const each_block_else = component.get_unique_name(`${this.var.name}_else`);
 
 			block.chunks.init.push(b`let ${each_block_else} = null;`);
@@ -264,7 +277,7 @@ export default class EachBlockWrapper extends Wrapper {
 			// TODO neaten this up... will end up with an empty line in the block
 			block.chunks.init.push(b`
 				if (!${this.vars.data_length}) {
-					${each_block_else} = ${this.else.block.name}(#ctx);
+					${each_block_else} = ${this.else.block.name}(${else_ctx});
 				}
 			`);
 
@@ -304,9 +317,9 @@ export default class EachBlockWrapper extends Wrapper {
 			if (this.else.block.has_update_method) {
 				this.updates.push(b`
 					if (!${this.vars.data_length} && ${each_block_else}) {
-						${each_block_else}.p(#ctx, #dirty);
+						${each_block_else}.p(${else_ctx}, #dirty);
 					} else if (!${this.vars.data_length}) {
-						${each_block_else} = ${this.else.block.name}(#ctx);
+						${each_block_else} = ${this.else.block.name}(${else_ctx});
 						${each_block_else}.c();
 						${has_transitions && b`@transition_in(${each_block_else}, 1);`}
 						${each_block_else}.m(${update_mount_node}, ${update_anchor_node});
@@ -321,7 +334,7 @@ export default class EachBlockWrapper extends Wrapper {
 							${destroy_block_else};
 						}
 					} else if (!${each_block_else}) {
-						${each_block_else} = ${this.else.block.name}(#ctx);
+						${each_block_else} = ${this.else.block.name}(${else_ctx});
 						${each_block_else}.c();
 						${has_transitions && b`@transition_in(${each_block_else}, 1);`}
 						${each_block_else}.m(${update_mount_node}, ${update_anchor_node});

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

@@ -2,6 +2,7 @@ import Renderer, { RenderOptions } from '../Renderer';
 import EachBlock from '../../nodes/EachBlock';
 import { x } from 'code-red';
 import { get_const_tags } from './shared/get_const_tags';
+import { Node } from 'estree';
 
 export default function(node: EachBlock, renderer: Renderer, options: RenderOptions) {
 	const args = [node.context_node];
@@ -16,7 +17,8 @@ export default function(node: EachBlock, renderer: Renderer, options: RenderOpti
 	if (node.else) {
 		renderer.push();
 		renderer.render(node.else.children, options);
-		const alternate = renderer.pop();
+		let alternate: Node = renderer.pop();
+		if (node.else.const_tags.length > 0) alternate = x`(() => { ${get_const_tags(node.else.const_tags)}; return ${alternate} })()`;
 
 		renderer.add_expression(x`${node.expression.node}.length ? ${consequent} : ${alternate}`);
 	} else {

test/runtime/samples/const-tag-each-else/_config.js

@@ -0,0 +1,26 @@
+export default {
+	html: `
+		<div>12 120 70, 30+4=34</div>
+		<div>35 350 120, 50+7=57</div>
+		<div>48 480 140, 60+8=68</div>
+	`,
+	async test({ component, target, assert }) {
+		component.boxes = [];
+		assert.htmlEqual(target.innerHTML, `
+			<div>10 * 2 = 20</div>
+		`);
+		
+		component.constant = 35;
+		assert.htmlEqual(target.innerHTML, `
+			<div>35 * 2 = 70</div>
+		`);
+
+		component.boxes = [
+			{width: 3, height: 4}
+		];
+
+		assert.htmlEqual(target.innerHTML, `
+			<div>12 420 245, 105+4=109</div>
+		`);
+	}
+};

test/runtime/samples/const-tag-each-else/main.svelte

@@ -0,0 +1,22 @@
+<script>
+	export let boxes = [
+		{width: 3, height: 4},
+		{width: 5, height: 7},
+		{width: 6, height: 8},
+	];
+	export let constant = 10;
+
+	function calculate(width, height, constant) {
+		return { area: width * height, volume: width * height * constant };
+	}
+</script>
+
+{#each boxes as box}
+	{@const {area, volume} = calculate(box.width, box.height, constant)}
+	{@const perimeter = (box.width + box.height) * constant}
+	{@const [width, height, sum] = [box.width * constant, box.height, box.width * constant + box.height]}
+	<div>{area} {volume} {perimeter}, {width}+{height}={sum}</div>
+{:else}
+	{@const double = constant + constant}
+	<div>{constant} * 2 = {double}</div>
+{/each}