Adds debug all option to debug tag

src/compile/nodes/DebugTag.ts

@@ -11,15 +11,21 @@ export default class DebugTag extends Tag {
 	) {
 		const { dependencies } = this.expression;
 
-		const condition = [...dependencies].map(d => `changed.${d}`).join(' || ');
+		// Debug all
+		if (dependencies.has('_')) {
+			block.builders.create.addLine('debugger;');
+			block.builders.update.addLine('debugger;');
+		} else {
+			const condition = [...dependencies].map(d => `changed.${d}`).join(' || ');
 
-		const identifiers = [...dependencies].join(', ');
+			const identifiers = [...dependencies].join(', ');
 
-		block.builders.update.addBlock(deindent`
-			if (${condition}) {
-				const { ${identifiers} } = ctx;
-				debugger;
-			}
-		`);
+			block.builders.update.addBlock(deindent`
+				if (${condition}) {
+					const { ${identifiers} } = ctx;
+					debugger;
+				}
+			`);
+		}
 	}
 }

src/parse/state/mustache.ts

@@ -315,17 +315,15 @@ export default function mustache(parser: Parser) {
 		});
 	} else if (parser.eat('@debug')) {
 		const expression = readExpression(parser);
-		
+	
 		parser.allowWhitespace();
 		parser.eat('}', true);
 
-		// console.error(expression);
-
 		parser.current().children.push({
 			start,
 			end: parser.index,
 			type: 'DebugTag',
-			expression
+			expression,
 		});
 	} else {
 		const expression = readExpression(parser);

src/validate/html/index.ts

@@ -74,6 +74,19 @@ export default function validateHtml(validator: Validator, html: Node) {
 			});
 		}
 
+		else if (node.type === 'DebugTag') {
+			// Only allow the `_` expression if it's by itself
+			// i.e. {@debug _, name } is redundantredundant-debug-all
+			const names = node.expression.expressions.map(e => e.name);
+
+			if (names.length > 0 && names.includes('_')) {
+				validator.error(node, {
+					code: 'redundant-debug-all',
+					message: `Combining other expressions with '_' is redundant`
+				});
+			}
+		}
+
 		if (validator.options.dev && isEmptyBlock(node)) {
 			validator.warn(node, {
 				code: `empty-block`,

test/validator/samples/redundant-debug-all/errors.json

@@ -0,0 +1,15 @@
+[{
+	"message": "Combining other expressions with '_' is redundant",
+	"start": {
+		"line": 1,
+		"column": 0,
+		"character": 0
+	},
+	"end":{
+		"line": 1,
+		"column": 16,
+		"character": 16
+	},
+	"pos": 0,
+	"code": "redundant-debug-all"
+}]

test/validator/samples/redundant-debug-all/input.html

@@ -0,0 +1,12 @@
+{@debug _, name}
+<div>Hello {name}!</div>
+
+<script>
+  export default {
+    data() {
+      return {
+        name: 'World'
+      }
+    }
+  }
+</script>