more refactoring

src/generators/dom/visitors/Element/Attribute.js

@@ -8,8 +8,6 @@ export default function visitAttribute ( generator, block, state, node, attribut
 	let metadata = state.namespace ? null : attributeLookup[ name ];
 	if ( metadata && metadata.appliesTo && !~metadata.appliesTo.indexOf( node.name ) ) metadata = null;
 
-	let dynamic = false;
-
 	const isIndirectlyBoundValue = name === 'value' && (
 		node.name === 'option' || // TODO check it's actually bound
 		node.name === 'input' && /^(checkbox|radio)$/.test( getStaticAttributeValue( node, 'type' ) )
@@ -22,112 +20,73 @@ export default function visitAttribute ( generator, block, state, node, attribut
 	// HTML5?
 	const method = name.slice( 0, 6 ) === 'xlink:' ? 'setXlinkAttribute' : 'setAttribute';
 
-	// attributes without values, e.g. <textarea readonly>
-	if ( attribute.value === true ) {
-		if ( propertyName ) {
-			block.builders.create.addLine(
-				`${state.parentNode}.${propertyName} = true;`
-			);
-		} else {
-			block.builders.create.addLine(
-				`${generator.helper( method )}( ${state.parentNode}, '${name}', true );`
-			);
-		}
+	const isDynamic = attribute.value !== true && attribute.value.length > 1 || ( attribute.value.length === 1 && attribute.value[0].type !== 'Text' );
 
-		// special case – autofocus. has to be handled in a bit of a weird way
-		if ( name === 'autofocus' ) {
-			block.autofocus = state.parentNode;
-		}
-	}
+	if ( isDynamic ) {
+		let value;
 
-	// empty string
-	else if ( attribute.value.length === 0 ) {
-		if ( propertyName ) {
-			block.builders.create.addLine(
-				`${state.parentNode}.${propertyName} = '';`
-			);
+		if ( attribute.value.length === 1 ) {
+			// single {{tag}} — may be a non-string
+			const { snippet } = generator.contextualise( block, attribute.value[0].expression );
+			value = snippet;
 		} else {
-			block.builders.create.addLine(
-				`${generator.helper( method )}( ${state.parentNode}, '${name}', '' );`
-			);
-		}
-	}
-
-	// static text or a single {{tag}}
-	else if ( attribute.value.length === 1 ) {
-		const value = attribute.value[0];
-
-		if ( value.type === 'Text' ) {
-			// static attributes
-			const result = JSON.stringify( value.data );
-
-			if ( propertyName ) {
-				block.builders.create.addLine(
-					`${state.parentNode}.${propertyName} = ${result};`
-				);
+			// '{{foo}} {{bar}}' — treat as string concatenation
+			value = ( attribute.value[0].type === 'Text' ? '' : `"" + ` ) + (
+				attribute.value.map( chunk => {
+					if ( chunk.type === 'Text' ) {
+						return JSON.stringify( chunk.data );
 					} else {
-				if ( name === 'xmlns' ) {
-					// special case
-					// TODO this attribute must be static – enforce at compile time
-					state.namespace = value.data;
+						const { snippet } = generator.contextualise( block, chunk.expression );
+						return `( ${snippet} )`;
 					}
-
-				block.builders.create.addLine(
-					`${generator.helper( method )}( ${state.parentNode}, '${name}', ${result} );`
+				}).join( ' + ' )
 			);
 		}
-		}
-
-		else {
-			dynamic = true;
-
-			// dynamic – but potentially non-string – attributes
-			const { snippet } = generator.contextualise( block, value.expression );
 
 		const last = `last_${state.parentNode}_${name.replace( /-/g, '_')}`;
-			block.builders.create.addLine( `var ${last} = ${snippet};` );
+		block.builders.create.addLine( `var ${last} = ${value};` );
 
 		const updater = propertyName ?
 			`${state.parentNode}.${propertyName} = ${last};` :
 			`${generator.helper( method )}( ${state.parentNode}, '${name}', ${last} );`;
 
 		block.builders.create.addLine( updater );
-
 		block.builders.update.addBlock( deindent`
-				if ( ( ${block.tmp()} = ${snippet} ) !== ${last} ) {
+			if ( ( ${block.tmp()} = ${value} ) !== ${last} ) {
 				${last} = ${block.tmp()};
 				${updater}
 			}
 		` );
 	}
-	}
 
 	else {
-		dynamic = true;
-
-		const value = ( attribute.value[0].type === 'Text' ? '' : `"" + ` ) + (
-			attribute.value.map( chunk => {
-				if ( chunk.type === 'Text' ) {
-					return JSON.stringify( chunk.data );
-				} else {
-					const { snippet } = generator.contextualise( block, chunk.expression );
-					return `( ${snippet} )`;
-				}
-			}).join( ' + ' )
-		);
+		const value = attribute.value === true ? 'true' :
+		              attribute.value.length === 0 ? `''` :
+		              JSON.stringify( attribute.value[0].data );
 
-		const updater = propertyName ?
+		const statement = propertyName ?
 			`${state.parentNode}.${propertyName} = ${value};` :
 			`${generator.helper( method )}( ${state.parentNode}, '${name}', ${value} );`;
 
-		block.builders.create.addLine( updater );
-		block.builders.update.addLine( updater );
+
+		block.builders.create.addLine( statement );
+
+		// special case – autofocus. has to be handled in a bit of a weird way
+		if ( attribute.value === true && name === 'autofocus' ) {
+			block.autofocus = state.parentNode;
+		}
+
+		// special case — xmlns
+		if ( name === 'xmlns' ) {
+			// TODO this attribute must be static – enforce at compile time
+			state.namespace = attribute.value[0].data;
+		}
 	}
 
 	if ( isIndirectlyBoundValue ) {
 		const updateValue = `${state.parentNode}.value = ${state.parentNode}.__value;`;
 
 		block.builders.create.addLine( updateValue );
-		if ( dynamic ) block.builders.update.addLine( updateValue );
+		if ( isDynamic ) block.builders.update.addLine( updateValue );
 	}
 }