more refactoring

src/generators/dom/visitors/attributes/addComponentBinding.js

@@ -1,77 +1,41 @@
 import deindent from '../../../../utils/deindent.js';
-import isReference from '../../../../utils/isReference.js';
 import flattenReference from '../../../../utils/flattenReference.js';
+import getSetter from './binding/getSetter.js';
 
 export default function createBinding ( generator, node, attribute, current, local ) {
-	const { name, parts, keypath } = flattenReference( attribute.value );
+	const { name } = flattenReference( attribute.value );
+	const { snippet, contexts, dependencies } = generator.contextualise( attribute.value );
 
-	const contextual = name in current.contexts;
+	if ( dependencies.length > 1 ) throw new Error( 'An unexpected situation arose. Please raise an issue at https://github.com/sveltejs/svelte/issues — thanks!' );
 
-	if ( contextual && !~local.allUsedContexts.indexOf( name ) ) {
+	contexts.forEach( context => {
-		local.allUsedContexts.push( name );
+		if ( !~local.allUsedContexts.indexOf( context ) ) local.allUsedContexts.push( context );
-	}
+	});
+
+	const contextual = name in current.contexts;
 
 	let obj;
 	let prop;
-	let value;
 
 	if ( contextual ) {
 		obj = current.listNames[ name ];
 		prop = current.indexNames[ name ];
-		value = keypath;
+	} else if ( attribute.value.type === 'MemberExpression' ) {
+		prop = `'[✂${attribute.value.property.start}-${attribute.value.property.end}✂]}'`;
+		obj = `root.[✂${attribute.value.object.start}-${attribute.value.object.end}✂]}`;
 	} else {
-		prop = `'${parts.slice( -1 )}'`;
+		obj = 'root';
-		obj = parts.length > 1 ? `root.${parts.slice( 0, -1 ).join( '.' )}` : `root`;
+		prop = `'${name}'`;
-		value = `root.${keypath}`;
-	}
-
-	local.bindings.push({ name: attribute.name, value, obj, prop });
-
-	let setter;
-
-	if ( contextual ) {
-		// find the top-level property that this is a child of
-		let fragment = current;
-		let prop = name;
-
-		do {
-			if ( fragment.expression && fragment.context === prop ) {
-				if ( !isReference( fragment.expression ) ) {
-					// TODO this should happen in prior validation step
-					throw new Error( `${prop} is read-only, it cannot be bound` );
 	}
 
-				prop = flattenReference( fragment.expression ).name;
+	local.bindings.push({
-			}
+		name: attribute.name,
-		} while ( fragment = fragment.parent );
+		value: snippet,
-
+		obj,
-		generator.expectedProperties[ prop ] = true;
+		prop
-
+	});
-		const listName = current.listNames[ name ];
-		const indexName = current.indexNames[ name ];
-
-		const context = local.isComponent ? `_context` : `__svelte`;
-
-		setter = deindent`
-			var list = this.${context}.${listName};
-			var index = this.${context}.${indexName};
-			list[index]${parts.slice( 1 ).map( part => `.${part}` ).join( '' )} = value;
-
-			component._set({ ${prop}: component.get( '${prop}' ) });
-		`;
-	} else {
-		if ( parts.length > 1 ) {
-			setter = deindent`
-				var ${name} = component.get( '${name}' );
-				${name}.${parts.slice( 1 ).join( '.' )} = value;
-				component._set({ ${name}: ${name} });
-			`;
-		} else {
-			setter = `component._set({ ${keypath}: value });`;
-		}
 
-		generator.expectedProperties[ name ] = true;
+	const setter = getSetter({ current, name, context: '_context', attribute, dependencies, snippet, value: 'value' });
-	}
 
 	generator.hasComplexBindings = true;
 
@@ -88,11 +52,9 @@ export default function createBinding ( generator, node, attribute, current, loc
 		});
 	` );
 
-	const dependencies = name in current.contexts ? current.contextDependencies[ name ] : [ name ];
-
 	local.update.addBlock( deindent`
 		if ( !${local.name}_updating && ${dependencies.map( dependency => `'${dependency}' in changed` ).join( '||' )} ) {
-			${local.name}._set({ ${attribute.name}: ${contextual ? keypath : `root.${keypath}`} });
+			${local.name}._set({ ${attribute.name}: ${snippet} });
 		}
 	` );
 }

src/generators/dom/visitors/attributes/addElementBinding.js

@@ -1,5 +1,6 @@
 import deindent from '../../../../utils/deindent.js';
 import flattenReference from '../../../../utils/flattenReference.js';
+import getSetter from './binding/getSetter.js';
 
 export default function createBinding ( generator, node, attribute, current, local ) {
 	const { name } = flattenReference( attribute.value );
@@ -17,30 +18,7 @@ export default function createBinding ( generator, node, attribute, current, loc
 	const value = getBindingValue( local, node, attribute, isMultipleSelect );
 	const eventName = getBindingEventName( node );
 
-	let setter;
+	let setter = getSetter({ current, name, context: '__svelte', attribute, dependencies, snippet, value });
-
-	if ( name in current.contexts ) {
-		const prop = dependencies[0];
-		const tail = attribute.value.type === 'MemberExpression' ? getTailSnippet( attribute.value ) : '';
-
-		setter = deindent`
-			var list = this.__svelte.${current.listNames[ name ]};
-			var index = this.__svelte.${current.indexNames[ name ]};
-			list[index]${tail} = ${value};
-
-			component._set({ ${prop}: component.get( '${prop}' ) });
-		`;
-	} else {
-		if ( attribute.value.type === 'MemberExpression' ) {
-			setter = deindent`
-				var ${name} = component.get( '${name}' );
-				${snippet} = ${value};
-				component._set({ ${name}: ${name} });
-			`;
-		} else {
-			setter = `component._set({ ${name}: ${value} });`;
-		}
-	}
 
 	// special case
 	if ( node.name === 'select' && !isMultipleSelect ) {

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

@@ -0,0 +1,34 @@
+import deindent from '../../../../../utils/deindent.js';
+
+export default function getSetter ({ current, name, context, attribute, dependencies, snippet, value }) {
+	if ( name in current.contexts ) {
+		const prop = dependencies[0];
+		const tail = attribute.value.type === 'MemberExpression' ? getTailSnippet( attribute.value ) : '';
+
+		return deindent`
+			var list = this.${context}.${current.listNames[ name ]};
+			var index = this.${context}.${current.indexNames[ name ]};
+			list[index]${tail} = ${value};
+
+			component._set({ ${prop}: component.get( '${prop}' ) });
+		`;
+	}
+	
+	if ( attribute.value.type === 'MemberExpression' ) {
+		return deindent`
+			var ${name} = component.get( '${name}' );
+			${snippet} = ${value};
+			component._set({ ${name}: ${name} });
+		`;
+	}
+	
+	return `component._set({ ${name}: ${value} });`;
+}
+
+function getTailSnippet ( node ) {
+	const end = node.end;
+	while ( node.type === 'MemberExpression' ) node = node.object;
+	const start = node.end;
+
+	return `[✂${start}-${end}✂]`;
+}