From abdce5c249828dfa42b55db643e6e937615ffaa0 Mon Sep 17 00:00:00 2001
From: Rich Harris <richard.a.harris@gmail.com>
Date: Thu, 23 Nov 2017 08:56:29 -0500
Subject: [PATCH] validate slot attribute placement

---
 .../shared/utils/isChildOfComponent.ts        |  3 --
 src/validate/html/validateElement.ts          | 45 ++++++++++++-------
 .../slot-attribute-invalid/errors.json        |  8 ++++
 .../samples/slot-attribute-invalid/input.html |  1 +
 4 files changed, 37 insertions(+), 20 deletions(-)
 create mode 100644 test/validator/samples/slot-attribute-invalid/errors.json
 create mode 100644 test/validator/samples/slot-attribute-invalid/input.html

diff --git a/src/generators/shared/utils/isChildOfComponent.ts b/src/generators/shared/utils/isChildOfComponent.ts
index 3246d27d35..2de64c4860 100644
--- a/src/generators/shared/utils/isChildOfComponent.ts
+++ b/src/generators/shared/utils/isChildOfComponent.ts
@@ -7,7 +7,4 @@ export default function isChildOfComponent(node: Node, generator: Generator) {
 		if (generator.components.has(node.name)) return true;
 		if (/-/.test(node.name)) return false;
 	}
-
-	// TODO do this in validation
-	throw new Error(`Element with a slot='...' attribute must be a descendant of a component or custom element`);
 }
\ No newline at end of file
diff --git a/src/validate/html/validateElement.ts b/src/validate/html/validateElement.ts
index 461b5aa52f..0d67b8002d 100644
--- a/src/validate/html/validateElement.ts
+++ b/src/validate/html/validateElement.ts
@@ -1,6 +1,6 @@
 import * as namespaces from '../../utils/namespaces';
 import validateEventHandler from './validateEventHandler';
-import { Validator } from '../index';
+import validate, { Validator } from '../index';
 import { Node } from '../../interfaces';
 
 const svg = /^(?:altGlyph|altGlyphDef|altGlyphItem|animate|animateColor|animateMotion|animateTransform|circle|clipPath|color-profile|cursor|defs|desc|discard|ellipse|feBlend|feColorMatrix|feComponentTransfer|feComposite|feConvolveMatrix|feDiffuseLighting|feDisplacementMap|feDistantLight|feDropShadow|feFlood|feFuncA|feFuncB|feFuncG|feFuncR|feGaussianBlur|feImage|feMerge|feMergeNode|feMorphology|feOffset|fePointLight|feSpecularLighting|feSpotLight|feTile|feTurbulence|filter|font|font-face|font-face-format|font-face-name|font-face-src|font-face-uri|foreignObject|g|glyph|glyphRef|hatch|hatchpath|hkern|image|line|linearGradient|marker|mask|mesh|meshgradient|meshpatch|meshrow|metadata|missing-glyph|mpath|path|pattern|polygon|polyline|radialGradient|rect|set|solidcolor|stop|switch|symbol|text|textPath|title|tref|tspan|unknown|use|view|vkern)$/;
@@ -191,22 +191,7 @@ export default function validateElement(
 			}
 
 			if (attribute.name === 'slot' && !isComponent) {
-				let i = stack.length;
-				while (i--) {
-					const parent = stack[i];
-					if (parent.type === 'Element' && validator.components.has(parent.name)) break;
-					if (parent.type === 'IfBlock' || parent.type === 'EachBlock') {
-						const message = `Cannot place slotted elements inside an ${parent.type === 'IfBlock' ? 'if' : 'each'}-block`;
-						validator.error(message, attribute.start);
-					}
-				}
-
-				if (isDynamic(attribute)) {
-					validator.error(
-						`slot attribute cannot have a dynamic value`,
-						attribute.start
-					);
-				}
+				checkSlotAttribute(validator, node, attribute, stack);
 			}
 		}
 	});
@@ -232,6 +217,32 @@ function checkTypeAttribute(validator: Validator, node: Node) {
 	return attribute.value[0].data;
 }
 
+function checkSlotAttribute(validator: Validator, node: Node, attribute: Node, stack: Node[]) {
+	if (isDynamic(attribute)) {
+		validator.error(
+			`slot attribute cannot have a dynamic value`,
+			attribute.start
+		);
+	}
+
+	let i = stack.length;
+	while (i--) {
+		const parent = stack[i];
+		if (parent.type === 'Element') {
+			// if we're inside a component or a custom element, gravy
+			if (validator.components.has(parent.name)) return;
+			if (/-/.test(parent.name)) return;
+		}
+
+		if (parent.type === 'IfBlock' || parent.type === 'EachBlock') {
+			const message = `Cannot place slotted elements inside an ${parent.type === 'IfBlock' ? 'if' : 'each'}-block`;
+			validator.error(message, attribute.start);
+		}
+	}
+
+	validator.error(`Element with a slot='...' attribute must be a descendant of a component or custom element`, attribute.start);
+}
+
 function isDynamic(attribute: Node) {
 	return attribute.value.length > 1 || attribute.value[0].type !== 'Text';
 }
diff --git a/test/validator/samples/slot-attribute-invalid/errors.json b/test/validator/samples/slot-attribute-invalid/errors.json
new file mode 100644
index 0000000000..aea1fa7db1
--- /dev/null
+++ b/test/validator/samples/slot-attribute-invalid/errors.json
@@ -0,0 +1,8 @@
+[{
+	"message": "Element with a slot='...' attribute must be a descendant of a component or custom element",
+	"loc": {
+		"line": 1,
+		"column": 5
+	},
+	"pos": 5
+}]
diff --git a/test/validator/samples/slot-attribute-invalid/input.html b/test/validator/samples/slot-attribute-invalid/input.html
new file mode 100644
index 0000000000..ed407bb894
--- /dev/null
+++ b/test/validator/samples/slot-attribute-invalid/input.html
@@ -0,0 +1 @@
+<div slot='foo'>invalid</div>
\ No newline at end of file