Merge pull request #322 from sveltejs/gh-249

throw error in dev mode for missing bound properties (#249)

src/generators/dom/index.js

@@ -319,7 +319,7 @@ export default function dom ( parsed, source, options, names ) {
 	if ( options.dev ) {
 		Object.keys( generator.expectedProperties ).forEach( prop => {
 			stateBlock.addLine(
-				`if ( !( '${prop}' in this._state ) ) throw new Error( "Component was created without expected data property 'foo'" );`
+				`if ( !( '${prop}' in this._state ) ) throw new Error( "Component was created without expected data property '${prop}'" );`
 			);
 		});
 	}

src/generators/dom/visitors/attributes/binding/index.js

@@ -72,6 +72,8 @@ export default function createBinding ( generator, node, attribute, current, loc
 			}
 		} while ( fragment = fragment.parent );
 
+		generator.expectedProperties[ prop ] = true;
+
 		const listName = current.listNames[ parts[0] ];
 		const indexName = current.indexNames[ parts[0] ];
 
@@ -84,7 +86,8 @@ export default function createBinding ( generator, node, attribute, current, loc
 
 			component._set({ ${prop}: component.get( '${prop}' ) });
 		`;
-	} else if ( deep ) {
+	} else {
+		if ( deep ) {
 			setter = deindent`
 				var ${parts[0]} = component.get( '${parts[0]}' );
 				${parts[0]}.${parts.slice( 1 ).join( '.' )} = ${value};
@@ -94,6 +97,9 @@ export default function createBinding ( generator, node, attribute, current, loc
 			setter = `component._set({ ${attribute.value}: ${value} });`;
 		}
 
+		generator.expectedProperties[ parts[0] ] = true;
+	}
+
 	// special case
 	if ( node.name === 'select' ) {
 		setter = `var selectedOption = ${local.name}.selectedOptions[0] || ${local.name}.options[0];\n` + setter;

test/generator/dev-warning-missing-data-binding/_config.js

@@ -0,0 +1,7 @@
+export default {
+	dev: true,
+
+	error ( assert, err ) {
+		assert.equal( err.message, `Component was created without expected data property 'value'` );
+	}
+};

test/generator/dev-warning-missing-data-binding/main.html

@@ -0,0 +1 @@
+<input bind:value>