WIP: separate create from mount

compiler/generate/index.js

@@ -15,28 +15,34 @@ export default function generate ( parsed, source, options ) {
 
 	const generator = {
 		addElement ( name, renderStatement, needsIdentifier = false ) {
-			const needsTeardown = generator.current.localElementDepth === 0;
-			if ( needsIdentifier || needsTeardown ) {
+			const isToplevel = generator.current.localElementDepth === 0;
+			if ( needsIdentifier || isToplevel ) {
 				generator.current.initStatements.push( deindent`
 					var ${name} = ${renderStatement};
-					${generator.appendToTarget( name )};
 				` );
+				generator.createMountStatement( name );
 			} else {
 				generator.current.initStatements.push( deindent`
 					${generator.current.target}.appendChild( ${renderStatement} );
 				` );
 			}
-			if ( needsTeardown ) {
+			if ( isToplevel ) {
 				generator.current.teardownStatements.push( deindent`
 					if ( detach ) ${name}.parentNode.removeChild( ${name} );
 				` );
 			}
 		},
-		appendToTarget ( name ) {
-			if ( generator.current.useAnchor && generator.current.target === 'target' ) {
-				return `anchor.parentNode.insertBefore( ${name}, anchor )`;
+
+		createMountStatement ( name ) {
+			if ( generator.current.target === 'target' ) {
+				generator.current.mountStatements.push( deindent`
+					target.insertBefore( ${name}, anchor );
+				` );
+			} else {
+				generator.current.initStatements.push( deindent`
+					${generator.current.target}.appendChild( ${name} );
+				` );
 			}
-			return `${generator.current.target}.appendChild( ${name} )`;
 		},
 
 		addRenderer ( fragment ) {
@@ -45,10 +51,17 @@ export default function generate ( parsed, source, options ) {
 			}
 
 			renderers.push( deindent`
-				function ${fragment.name} ( ${fragment.params}, component, target${fragment.useAnchor ? ', anchor' : ''} ) {
+				function ${fragment.name} ( ${fragment.params}, component ) {
+					var target, anchor;
 					${fragment.initStatements.join( '\n\n' )}
 
 					return {
+						mount: function ( _target, _anchor ) {
+							target = _target;
+							anchor = _anchor;
+							${fragment.mountStatements.join( '\n\n' )}
+						},
+
 						update: function ( changed, ${fragment.params} ) {
 							${fragment.updateStatements.join( '\n\n' )}
 						},
@@ -236,6 +249,7 @@ export default function generate ( parsed, source, options ) {
 		localElementDepth: 0,
 
 		initStatements: [],
+		mountStatements: [],
 		updateStatements: [],
 		teardownStatements: [],
 
@@ -364,13 +378,17 @@ export default function generate ( parsed, source, options ) {
 	if ( generator.hasComplexBindings ) {
 		initStatements.push( deindent`
 			this.__bindings = [];
-			var mainFragment = renderMainFragment( state, this, options.target );
+			var mainFragment = renderMainFragment( state, this );
+			if ( options.target ) this.mount( options.target );
 			while ( this.__bindings.length ) this.__bindings.pop()();
 		` );
 
 		setStatements.push( `while ( this.__bindings.length ) this.__bindings.pop()();` );
 	} else {
-		initStatements.push( `var mainFragment = renderMainFragment( state, this, options.target );` );
+		initStatements.push( deindent`
+			var mainFragment = renderMainFragment( state, this );
+			if ( options.target ) this.mount( options.target );
+		` );
 	}
 
 	if ( generator.hasComponents ) {
@@ -449,6 +467,10 @@ export default function generate ( parsed, source, options ) {
 				${setStatements.join( '\n\n' )}
 			};
 
+			this.mount = function mount ( target, anchor ) {
+				mainFragment.mount( target, anchor );
+			}
+
 			this.observe = function ( key, callback, options ) {
 				var group = ( options && options.defer ) ? observers.deferred : observers.immediate;
 

compiler/generate/visitors/EachBlock.js

@@ -6,10 +6,13 @@ export default {
 		const i = generator.counters.each++;
 		const name = `eachBlock_${i}`;
 		const anchor = `${name}_anchor`;
+		const iterations = `${name}_iterations`;
 		const renderer = `renderEachBlock_${i}`;
 
 		const listName = `${name}_value`;
 
+		const isToplevel = generator.current.localElementDepth === 0;
+
 		generator.addSourcemapLocations( node.expression );
 
 		const { dependencies, snippet } = generator.contextualise( node.expression );
@@ -18,39 +21,44 @@ export default {
 
 		generator.current.initStatements.push( deindent`
 			var ${name}_value = ${snippet};
-			var ${name}_fragment = document.createDocumentFragment();
-			var ${name}_iterations = [];
+			var ${iterations} = [];
 
 			for ( var i = 0; i < ${name}_value.length; i += 1 ) {
-				${name}_iterations[i] = ${renderer}( ${generator.current.params}, ${listName}, ${listName}[i], i, component, ${name}_fragment );
+				${iterations}[i] = ${renderer}( ${generator.current.params}, ${listName}, ${listName}[i], i, component );
+				${!isToplevel ? `${iterations}[i].mount( ${anchor}.parentNode, ${anchor} );` : ''}
 			}
-
-			${anchor}.parentNode.insertBefore( ${name}_fragment, ${anchor} );
 		` );
 
+		if ( isToplevel ) {
+			generator.current.mountStatements.push( deindent`
+				for ( var i = 0; i < ${iterations}.length; i += 1 ) {
+					${iterations}[i].mount( ${anchor}.parentNode, ${anchor} );
+				}
+			` );
+		}
+
 		generator.current.updateStatements.push( deindent`
 			var ${name}_value = ${snippet};
 
 			for ( var i = 0; i < ${name}_value.length; i += 1 ) {
-				if ( !${name}_iterations[i] ) {
-					${name}_iterations[i] = ${renderer}( ${generator.current.params}, ${listName}, ${listName}[i], i, component, ${name}_fragment );
+				if ( !${iterations}[i] ) {
+					${iterations}[i] = ${renderer}( ${generator.current.params}, ${listName}, ${listName}[i], i, component );
+					${iterations}[i].mount( ${anchor}.parentNode, ${anchor} );
 				} else {
-					${name}_iterations[i].update( changed, ${generator.current.params}, ${listName}, ${listName}[i], i );
+					${iterations}[i].update( changed, ${generator.current.params}, ${listName}, ${listName}[i], i );
 				}
 			}
 
-			for ( var i = ${name}_value.length; i < ${name}_iterations.length; i += 1 ) {
-				${name}_iterations[i].teardown( true );
+			for ( var i = ${name}_value.length; i < ${iterations}.length; i += 1 ) {
+				${iterations}[i].teardown( true );
 			}
 
-			${anchor}.parentNode.insertBefore( ${name}_fragment, ${anchor} );
-			${name}_iterations.length = ${listName}.length;
+			${iterations}.length = ${listName}.length;
 		` );
 
-		const needsTeardown = generator.current.localElementDepth === 0;
 		generator.current.teardownStatements.push( deindent`
-			for ( var i = 0; i < ${name}_iterations.length; i += 1 ) {
-				${name}_iterations[i].teardown( ${needsTeardown ? 'detach' : 'false'} );
+			for ( var i = 0; i < ${iterations}.length; i += 1 ) {
+				${iterations}[i].teardown( ${isToplevel ? 'detach' : 'false'} );
 			}
 		` );
 
@@ -88,6 +96,7 @@ export default {
 			params,
 
 			initStatements: [],
+			mountStatements: [],
 			updateStatements: [ Object.keys( contexts ).map( contextName => {
 				const listName = listNames[ contextName ];
 				const indexName = indexNames[ contextName ];

compiler/generate/visitors/Element.js

@@ -15,6 +15,7 @@ export default {
 			allUsedContexts: new Set(),
 
 			init: [],
+			mount: [],
 			update: [],
 			teardown: []
 		};
@@ -57,19 +58,22 @@ export default {
 					${statements.join( '\n\n' )}
 
 					var ${name} = new template.components.${node.name}({
-						target: ${generator.current.target},
+						target: ${!shouldDetach ? generator.current.target: 'null'},
 						parent: component,
 						data: ${name}_initialData
 					});
 				` );
 			} else {
 				local.init.unshift( deindent`
 					var ${name} = new template.components.${node.name}({
-						target: ${generator.current.target},
+						target: ${!shouldDetach ? generator.current.target: 'null'},
 						parent: component
 					});
 				` );
 			}
+			if ( shouldDetach ) {
+				local.mount.unshift( `${name}.mount( target, anchor );` );
+			}
 
 			if ( local.dynamicAttributes.length ) {
 				const updates = local.dynamicAttributes.map( attribute => {
@@ -146,6 +150,7 @@ export default {
 
 		generator.current.initStatements.push( local.init.join( '\n' ) );
 		if ( local.update.length ) generator.current.updateStatements.push( local.update.join( '\n' ) );
+		if ( local.mount.length ) generator.current.mountStatements.push( local.mount.join( '\n' ) );
 		generator.current.teardownStatements.push( local.teardown.join( '\n' ) );
 
 		generator.push({
@@ -166,7 +171,6 @@ export default {
 
 		if ( isComponent ) return;
 
-		generator.current.initStatements.push(
-			generator.appendToTarget( name ) );
+		generator.createMountStatement( name );
 	}
 };

compiler/generate/visitors/IfBlock.js

@@ -11,18 +11,19 @@ function generateBlock ( generator, node, name ) {
 		localElementDepth: 0,
 
 		initStatements: [],
+		mountStatements: [],
 		updateStatements: [],
 		teardownStatements: [],
 
 		counter: counter()
 	});
 	node.children.forEach( generator.visit );
-	//generator.visit( node.children );
 	generator.addRenderer( generator.current );
 	generator.pop();
 	// unset the children, to avoid them being visited again
 	node.children = [];
 }
+
 function getConditionsAndBlocks ( generator, node, _name, i = 0 ) {
 	generator.addSourcemapLocations( node.expression );
 	const name = `${_name}_${i}`;
@@ -54,12 +55,13 @@ export default {
 	enter ( generator, node ) {
 		const i = generator.counters.if++;
 
-		const { params, target } = generator.current;
+		const { params } = generator.current;
 		const name = `ifBlock_${i}`;
 		const anchor = `${name}_anchor`;
 		const getBlock = `getBlock_${i}`;
 		const currentBlock = `currentBlock_${i}`;
 
+		const isToplevel = generator.current.localElementDepth === 0;
 		const conditionsAndBlocks = getConditionsAndBlocks( generator, node, `renderIfBlock_${i}` );
 
 		generator.addElement( anchor, `document.createComment( ${JSON.stringify( `#if ${generator.source.slice( node.expression.start, node.expression.end )}` )} )`, true );
@@ -72,20 +74,30 @@ export default {
 			}
 
 			var ${currentBlock} = ${getBlock}( ${params} );
-			var ${name} = ${currentBlock} && ${currentBlock}( ${params}, component, ${target}, ${anchor} );
+			var ${name} = ${currentBlock} && ${currentBlock}( ${params}, component );
 		` );
 
+		const mountStatement = `if ( ${name} ) ${name}.mount( ${anchor}.parentNode, ${anchor} );`;
+		if ( isToplevel ) {
+			generator.current.mountStatements.push( mountStatement );
+		} else {
+			generator.current.initStatements.push( mountStatement );
+		}
+
 		generator.current.updateStatements.push( deindent`
 			var _${currentBlock} = ${currentBlock};
 			${currentBlock} = ${getBlock}( ${params} );
 			if ( _${currentBlock} === ${currentBlock} && ${name}) {
 				${name}.update( changed, ${params} );
 			} else {
 				if ( ${name} ) ${name}.teardown( true );
-				${name} = ${currentBlock} && ${currentBlock}( ${params}, component, ${target}, ${anchor} );
+				${name} = ${currentBlock} && ${currentBlock}( ${params}, component );
+				if ( ${name} ) ${name}.mount( ${anchor}.parentNode, ${anchor} );
 			}
 		` );
 
-		generator.current.teardownStatements.push( `if ( ${name} ) ${name}.teardown( detach );` );
+		generator.current.teardownStatements.push( deindent`
+			if ( ${name} ) ${name}.teardown( ${isToplevel ? 'detach' : 'false'} );
+		` );
 	}
 };

test/compiler/each-block-random-permute/_config.js

@@ -0,0 +1,33 @@
+const VALUES = Array.from( 'abcdefghijklmnopqrstuvwxyz' );
+
+function permute () {
+	const values = VALUES.slice();
+	const number = Math.floor(Math.random() * VALUES.length);
+	const permuted = [];
+	for (let i = 0; i < number; i++) {
+		permuted.push( ...values.splice( Math.floor( Math.random() * ( number - i ) ), 1 ) );
+	}
+
+	return {
+		data: permuted,
+		expected: permuted.length ? `(${permuted.join(')(')})` : ''
+	};
+}
+
+let step = permute();
+
+export default {
+	data: {
+		values: step.data
+	},
+
+	html: step.expected,
+
+	test ( assert, component, target ) {
+		for (let i = 0; i < 100; i++) {
+			step = permute();
+			component.set({ values: step.data });
+			assert.htmlEqual( target.innerHTML, step.expected );
+		}
+	}
+};

test/compiler/each-block-random-permute/main.html

@@ -0,0 +1,3 @@
+{{#each values as value}}
+	({{value}})
+{{/each}}