Merge branch 'master' into gh-371

src/generators/Generator.js

@@ -18,15 +18,15 @@ export default class Generator {
 		this.options = options;
 
 		this.imports = [];
-		this.helpers = {};
+		this.helpers = new Set();
-		this.components = {};
+		this.components = new Set();
-		this.events = {};
+		this.events = new Set();
 
 		this.bindingGroups = [];
 
 		// track which properties are needed, so we can provide useful info
 		// in dev mode
-		this.expectedProperties = {};
+		this.expectedProperties = new Set();
 
 		this.elementDepth = 0;
 
@@ -37,11 +37,11 @@ export default class Generator {
 
 		// allow compiler to deconflict user's `import { get } from 'whatever'` and
 		// Svelte's builtin `import { get, ... } from 'svelte/shared.js'`;
-		this.importedNames = {};
+		this.importedNames = new Set();
 
-		this.aliases = {};
+		this.aliases = new Map();
 
-		this._callbacks = {};
+		this._callbacks = new Map();
 	}
 
 	addSourcemapLocations ( node ) {
@@ -54,17 +54,17 @@ export default class Generator {
 	}
 
 	alias ( name ) {
-		if ( !( name in this.aliases ) ) {
+		if ( !( this.aliases.has( name ) ) ) {
 			let alias = name;
 			let i = 1;
 			while ( alias in this.importedNames ) {
 				alias = `${name}$${i++}`;
 			}
 
-			this.aliases[ name ] = alias;
+			this.aliases.set( name, alias );
 		}
 
-		return this.aliases[ name ];
+		return this.aliases.get( name );
 	}
 
 	contextualise ( expression, isEventHandler ) {
@@ -91,7 +91,7 @@ export default class Generator {
 					const { name } = flattenReference( node );
 					if ( scope.has( name ) ) return;
 
-					if ( parent && parent.type === 'CallExpression' && node === parent.callee && helpers[ name ] ) {
+					if ( parent && parent.type === 'CallExpression' && node === parent.callee && helpers.has( name ) ) {
 						code.prependRight( node.start, `${self.alias( 'template' )}.helpers.` );
 					}
 
@@ -99,19 +99,19 @@ export default class Generator {
 						// noop
 					}
 
-					else if ( name in contexts ) {
+					else if ( contexts.has( name ) ) {
-						const context = contexts[ name ];
+						const context = contexts.get( name );
 						if ( context !== name ) {
 							// this is true for 'reserved' names like `root` and `component`
 							code.overwrite( node.start, node.start + name.length, context, true );
 						}
 
-						dependencies.push( ...contextDependencies[ name ] );
+						dependencies.push( ...contextDependencies.get( name ) );
 						if ( !~usedContexts.indexOf( name ) ) usedContexts.push( name );
 					}
 
-					else if ( indexes[ name ] ) {
+					else if ( indexes.has( name ) ) {
-						const context = indexes[ name ];
+						const context = indexes.get( name );
 						if ( !~usedContexts.indexOf( context ) ) usedContexts.push( context );
 					}
 
@@ -145,7 +145,7 @@ export default class Generator {
 		});
 
 		dependencies.forEach( name => {
-			this.expectedProperties[ name ] = true;
+			this.expectedProperties.add( name );
 		});
 
 		return {
@@ -157,7 +157,7 @@ export default class Generator {
 	}
 
 	fire ( eventName, data ) {
-		const handlers = eventName in this._callbacks && this._callbacks[ eventName ].slice();
+		const handlers = this._callbacks.has( eventName ) && this._callbacks.get( eventName ).slice();
 		if ( !handlers ) return;
 
 		for ( let i = 0; i < handlers.length; i += 1 ) {
@@ -287,7 +287,7 @@ export default class Generator {
 				} else {
 					const { declarations } = annotateWithScopes( js );
 					let template = 'template';
-					for ( let i = 1; template in declarations; template = `template$${i++}` );
+					for ( let i = 1; declarations.has( template ); template = `template$${i++}` );
 
 					this.code.overwrite( defaultExport.start, defaultExport.declaration.start, `var ${template} = ` );
 
@@ -312,7 +312,7 @@ export default class Generator {
 			[ 'helpers', 'events', 'components' ].forEach( key => {
 				if ( templateProperties[ key ] ) {
 					templateProperties[ key ].value.properties.forEach( prop => {
-						this[ key ][ prop.key.name ] = prop.value;
+						this[ key ].add( prop.key.name );
 					});
 				}
 			});
@@ -354,8 +354,11 @@ export default class Generator {
 	}
 
 	on ( eventName, handler ) {
-		const handlers = this._callbacks[ eventName ] || ( this._callbacks[ eventName ] = [] );
+		if ( this._callbacks.has( eventName ) ) {
-		handlers.push( handler );
+			this._callbacks.get( eventName ).push( handler );
+		} else {
+			this._callbacks.set( eventName, [ handler ] );
+		}
 	}
 
 	pop () {

src/generators/annotateWithScopes.js

@@ -7,15 +7,15 @@ export default function annotateWithScopes ( expression ) {
 		enter ( node ) {
 			if ( /Function/.test( node.type ) ) {
 				if ( node.type === 'FunctionDeclaration' ) {
-					scope.declarations[ node.id.name ] = true;
+					scope.declarations.add( node.id.name );
 				} else {
 					node._scope = scope = new Scope( scope, false );
-					if ( node.id ) scope.declarations[ node.id.name ] = true;
+					if ( node.id ) scope.declarations.add( node.id.name );
 				}
 
 				node.params.forEach( param => {
 					extractNames( param ).forEach( name => {
-						scope.declarations[ name ] = true;
+						scope.declarations.add( name );
 					});
 				});
 			}
@@ -47,7 +47,7 @@ class Scope {
 	constructor ( parent, block ) {
 		this.parent = parent;
 		this.block = block;
-		this.declarations = Object.create( null );
+		this.declarations = new Set();
 	}
 
 	addDeclaration ( node ) {
@@ -56,16 +56,16 @@ class Scope {
 		} else if ( node.type === 'VariableDeclaration' ) {
 			node.declarations.forEach( declarator => {
 				extractNames( declarator.id ).forEach( name => {
-					this.declarations[ name ] = true;
+					this.declarations.add( name );
 				});
 			});
 		} else {
-			this.declarations[ node.id.name ] = true;
+			this.declarations.add( node.id.name );
 		}
 	}
 
 	has ( name ) {
-		return name in this.declarations || this.parent && this.parent.has( name );
+		return this.declarations.has( name ) || this.parent && this.parent.has( name );
 	}
 }
 

src/generators/dom/index.js

@@ -12,7 +12,7 @@ class DomGenerator extends Generator {
 	constructor ( parsed, source, name, names, visitors, options ) {
 		super( parsed, source, name, names, visitors, options );
 		this.renderers = [];
-		this.uses = {};
+		this.uses = new Set();
 
 		// allow compiler to deconflict user's `import { get } from 'whatever'` and
 		// Svelte's builtin `import { get, ... } from 'svelte/shared.js'`;
@@ -24,7 +24,7 @@ class DomGenerator extends Generator {
 			metaBindings: new CodeBuilder()
 		};
 
-		this.importedComponents = {};
+		this.importedComponents = new Map();
 	}
 
 	addElement ( name, renderStatement, needsIdentifier = false ) {
@@ -144,7 +144,7 @@ class DomGenerator extends Generator {
 			name = `${name}Dev`;
 		}
 
-		this.uses[ name ] = true;
+		this.uses.add( name );
 
 		return this.alias( name );
 	}
@@ -184,15 +184,15 @@ export default function dom ( parsed, source, options, names ) {
 		templateProperties.components.value.properties.forEach( property => {
 			const key = property.key.name;
 			const value = source.slice( property.value.start, property.value.end );
-			if ( generator.importedNames[ value ] ) {
+			if ( generator.importedNames.has( value ) ) {
-				generator.importedComponents[ key ] = value;
+				generator.importedComponents.set( key, value );
 			} else {
 				hasNonImportedComponent = true;
 			}
 		});
 		if ( hasNonImportedComponent ) {
 			// remove the specific components that were imported, as we'll refer to them directly
-			Object.keys( generator.importedComponents ).forEach( key => {
+			Array.from( generator.importedComponents.keys() ).forEach( key => {
 				removeObjectKey( generator, templateProperties.components.value, key );
 			});
 		} else {
@@ -208,12 +208,12 @@ export default function dom ( parsed, source, options, names ) {
 		localElementDepth: 0,
 		key: null,
 
-		contexts: {},
+		contexts: new Map(),
-		indexes: {},
+		indexes: new Map(),
 
 		params: [ 'root' ],
-		indexNames: {},
+		indexNames: new Map(),
-		listNames: {},
+		listNames: new Map(),
 
 		builders: getBuilders(),
 		getUniqueName: generator.getUniqueNameMaker()
@@ -350,7 +350,7 @@ export default function dom ( parsed, source, options, names ) {
 	}
 
 	if ( options.dev ) {
-		Object.keys( generator.expectedProperties ).forEach( prop => {
+		generator.expectedProperties.forEach( prop => {
 			constructorBlock.addLine(
 				`if ( !( '${prop}' in this._state ) ) throw new Error( "Component was created without expected data property '${prop}'" );`
 			);
@@ -422,17 +422,17 @@ export default function dom ( parsed, source, options, names ) {
 			throw new Error( `Components with shared helpers must be compiled to ES2015 modules (format: 'es')` );
 		}
 
-		const names = Object.keys( generator.uses ).map( name => {
+		const names = Array.from( generator.uses ).map( name => {
-			return name !== generator.aliases[ name ] ? `${name} as ${generator.aliases[ name ]}` : name;
+			return name !== generator.aliases.get( name ) ? `${name} as ${generator.aliases.get( name )}` : name;
 		});
 
 		builders.main.addLineAtStart(
 			`import { ${names.join( ', ' )} } from ${JSON.stringify( sharedPath )}`
 		);
 	} else {
-		Object.keys( generator.uses ).forEach( key => {
+		generator.uses.forEach( key => {
 			const fn = shared[ key ]; // eslint-disable-line import/namespace
-			builders.main.addBlock( fn.toString().replace( /^function [^(]*/, 'function ' + generator.aliases[ key ] ) );
+			builders.main.addBlock( fn.toString().replace( /^function [^(]*/, 'function ' + generator.aliases.get( key ) ) );
 		});
 	}
 

src/generators/dom/visitors/Component.js

@@ -32,8 +32,8 @@ export default {
 			const initialProps = local.allUsedContexts.map( contextName => {
 				if ( contextName === 'root' ) return `root: root`;
 
-				const listName = generator.current.listNames[ contextName ];
+				const listName = generator.current.listNames.get( contextName );
-				const indexName = generator.current.indexNames[ contextName ];
+				const indexName = generator.current.indexNames.get( contextName );
 
 				return `${listName}: ${listName},\n${indexName}: ${indexName}`;
 			}).join( ',\n' );
@@ -41,8 +41,8 @@ export default {
 			const updates = local.allUsedContexts.map( contextName => {
 				if ( contextName === 'root' ) return `${name}._context.root = root;`;
 
-				const listName = generator.current.listNames[ contextName ];
+				const listName = generator.current.listNames.get( contextName );
-				const indexName = generator.current.indexNames[ contextName ];
+				const indexName = generator.current.indexNames.get( contextName );
 
 				return `${name}._context.${listName} = ${listName};\n${name}._context.${indexName} = ${indexName};`;
 			}).join( '\n' );
@@ -106,7 +106,7 @@ export default {
 			componentInitProperties.push(`data: ${name}_initialData`);
 		}
 
-		const expression = node.name === ':Self' ? generator.name : generator.importedComponents[ node.name ] || `${generator.alias( 'template' )}.components.${node.name}`;
+		const expression = node.name === ':Self' ? generator.name : generator.importedComponents.get( node.name ) || `${generator.alias( 'template' )}.components.${node.name}`;
 
 		local.init.addBlockAtStart( deindent`
 			${statements.join( '\n\n' )}

src/generators/dom/visitors/EachBlock.js

@@ -2,10 +2,7 @@ import CodeBuilder from '../../../utils/CodeBuilder.js';
 import deindent from '../../../utils/deindent.js';
 import getBuilders from '../utils/getBuilders.js';
 
-const reserved = {
+const reserved = new Set( [ 'component', 'root' ] );
-	component: true,
-	root: true
-};
 
 export default {
 	enter ( generator, node ) {
@@ -171,28 +168,29 @@ export default {
 			generator.generateBlock( node.else, renderElse );
 		}
 
-		const indexNames = Object.assign( {}, generator.current.indexNames );
+		const indexNames = new Map( generator.current.indexNames );
-		const indexName = indexNames[ node.context ] = ( node.index || `${node.context}__index` );
+		const indexName = node.index || `${node.context}__index`;
+		indexNames.set( node.context, indexName );
 
-		const listNames = Object.assign( {}, generator.current.listNames );
+		const listNames = new Map( generator.current.listNames );
-		listNames[ node.context ] = listName;
+		listNames.set( node.context, listName );
 
 		// ensure that contexts like `root` or `component` don't blow up the whole show
 		let context = node.context;
 		let c = 1;
 
-		while ( context in reserved || ~generator.current.params.indexOf( context ) ) {
+		while ( reserved.has( context ) || ~generator.current.params.indexOf( context ) ) {
 			context = `${node.context}$${c++}`;
 		}
 
-		const contexts = Object.assign( {}, generator.current.contexts );
+		const contexts = new Map( generator.current.contexts );
-		contexts[ node.context ] = context;
+		contexts.set( node.context, context );
 
-		const indexes = Object.assign( {}, generator.current.indexes );
+		const indexes = new Map( generator.current.indexes );
-		if ( node.index ) indexes[ indexName ] = node.context;
+		if ( node.index ) indexes.set( indexName, node.context );
 
-		const contextDependencies = Object.assign( {}, generator.current.contextDependencies );
+		const contextDependencies = new Map( generator.current.contextDependencies );
-		contextDependencies[ node.context ] = dependencies;
+		contextDependencies.set( node.context, dependencies );
 
 		const blockParams = generator.current.params.concat( listName, context, indexName );
 

src/generators/dom/visitors/Element.js

@@ -14,7 +14,8 @@ export default {
 			return meta[ node.name ].enter( generator, node );
 		}
 
-		const isComponent = node.name in generator.components || node.name === ':Self';
+		const isComponent = generator.components.has( node.name ) || node.name === ':Self';
+
 		if ( isComponent ) {
 			return Component.enter( generator, node );
 		}
@@ -41,8 +42,8 @@ export default {
 			const initialProps = local.allUsedContexts.map( contextName => {
 				if ( contextName === 'root' ) return `root: root`;
 
-				const listName = generator.current.listNames[ contextName ];
+				const listName = generator.current.listNames.get( contextName );
-				const indexName = generator.current.indexNames[ contextName ];
+				const indexName = generator.current.indexNames.get( contextName );
 
 				return `${listName}: ${listName},\n${indexName}: ${indexName}`;
 			}).join( ',\n' );
@@ -50,8 +51,8 @@ export default {
 			const updates = local.allUsedContexts.map( contextName => {
 				if ( contextName === 'root' ) return `${name}.__svelte.root = root;`;
 
-				const listName = generator.current.listNames[ contextName ];
+				const listName = generator.current.listNames.get( contextName );
-				const indexName = generator.current.indexNames[ contextName ];
+				const indexName = generator.current.indexNames.get( contextName );
 
 				return `${name}.__svelte.${listName} = ${listName};\n${name}.__svelte.${indexName} = ${indexName};`;
 			}).join( '\n' );
@@ -114,7 +115,8 @@ export default {
 			return;
 		}
 
-		const isComponent = node.name in generator.components;
+		const isComponent = generator.components.has( node.name );
+
 		if ( isComponent ) {
 			return Component.leave( generator, node );
 		}

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

@@ -94,8 +94,8 @@ export default function addComponentAttributes ( generator, node, local ) {
 			const declarations = usedContexts.map( name => {
 				if ( name === 'root' ) return 'var root = this._context.root;';
 
-				const listName = generator.current.listNames[ name ];
+				const listName = generator.current.listNames.get( name );
-				const indexName = generator.current.indexNames[ name ];
+				const indexName = generator.current.indexNames.get( name );
 
 				return `var ${listName} = this._context.${listName}, ${indexName} = this._context.${indexName}, ${name} = ${listName}[${indexName}]`;
 			});

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

@@ -12,14 +12,14 @@ export default function createBinding ( generator, node, attribute, current, loc
 		if ( !~local.allUsedContexts.indexOf( context ) ) local.allUsedContexts.push( context );
 	});
 
-	const contextual = name in current.contexts;
+	const contextual = current.contexts.has( name );
 
 	let obj;
 	let prop;
 
 	if ( contextual ) {
-		obj = current.listNames[ name ];
+		obj = current.listNames.get( name );
-		prop = current.indexNames[ name ];
+		prop = current.indexNames.get( name );
 	} 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}✂]}`;

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

@@ -171,8 +171,8 @@ export default function addElementAttributes ( generator, node, local ) {
 			const declarations = usedContexts.map( name => {
 				if ( name === 'root' ) return 'var root = this.__svelte.root;';
 
-				const listName = generator.current.listNames[ name ];
+				const listName = generator.current.listNames.get( name );
-				const indexName = generator.current.indexNames[ name ];
+				const indexName = generator.current.indexNames.get( name );
 
 				return `var ${listName} = this.__svelte.${listName}, ${indexName} = this.__svelte.${indexName}, ${name} = ${listName}[${indexName}]`;
 			});
@@ -180,7 +180,7 @@ export default function addElementAttributes ( generator, node, local ) {
 			const handlerName = generator.current.getUniqueName( `${name}Handler` );
 			const handlerBody = ( declarations.length ? declarations.join( '\n' ) + '\n\n' : '' ) + `[✂${attribute.expression.start}-${attribute.expression.end}✂];`;
 
-			if ( name in generator.events ) {
+			if ( generator.events.has( name ) ) {
 				local.init.addBlock( deindent`
 					var ${handlerName} = ${generator.alias( 'template' )}.events.${name}.call( component, ${local.name}, function ( event ) {
 						${handlerBody}

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

@@ -1,19 +1,19 @@
 import deindent from '../../../../../utils/deindent.js';
 
 export default function getSetter ({ current, name, context, attribute, dependencies, snippet, value }) {
-	if ( name in current.contexts ) {
+	if ( current.contexts.has( name ) ) {
 		const prop = dependencies[0];
 		const tail = attribute.value.type === 'MemberExpression' ? getTailSnippet( attribute.value ) : '';
 
 		return deindent`
-			var list = this.${context}.${current.listNames[ name ]};
+			var list = this.${context}.${current.listNames.get( name )};
-			var index = this.${context}.${current.indexNames[ name ]};
+			var index = this.${context}.${current.indexNames.get( name )};
 			list[index]${tail} = ${value};
 
 			component._set({ ${prop}: component.get( '${prop}' ) });
 		`;
 	}
-	
+
 	if ( attribute.value.type === 'MemberExpression' ) {
 		return deindent`
 			var ${name} = component.get( '${name}' );
@@ -21,7 +21,7 @@ export default function getSetter ({ current, name, context, attribute, dependen
 			component._set({ ${name}: ${name} });
 		`;
 	}
-	
+
 	return `component._set({ ${name}: ${value} });`;
 }
 
@@ -31,4 +31,4 @@ function getTailSnippet ( node ) {
 	const start = node.end;
 
 	return `[✂${start}-${end}✂]`;
-}
+}

src/generators/server-side-rendering/index.js

@@ -52,8 +52,8 @@ export default function ssr ( parsed, source, options, names ) {
 
 	// create main render() function
 	generator.push({
-		contexts: {},
+		contexts: new Map(),
-		indexes: {},
+		indexes: new Map(),
 		conditions: []
 	});
 

src/generators/server-side-rendering/visitors/Component.js

@@ -45,7 +45,7 @@ export default {
 			})
 			.concat( bindings.map( binding => {
 				const { name, keypath } = flattenReference( binding.value );
-				const value = name in generator.current.contexts ? keypath : `root.${keypath}`;
+				const value = generator.current.contexts.has( name ) ? keypath : `root.${keypath}`;
 				return `${binding.name}: ${value}`;
 			}))
 			.join( ', ' );

src/generators/server-side-rendering/visitors/EachBlock.js

@@ -7,14 +7,14 @@ export default {
 
 		// TODO should this be the generator's job? It's duplicated between
 		// here and the equivalent DOM compiler visitor
-		const contexts = Object.assign( {}, generator.current.contexts );
+		const contexts = new Map( generator.current.contexts );
-		contexts[ node.context ] = node.context;
+		contexts.set( node.context, node.context );
 
-		const indexes = Object.assign( {}, generator.current.indexes );
+		const indexes = new Map( generator.current.indexes );
-		if ( node.index ) indexes[ node.index ] = node.context;
+		if ( node.index ) indexes.set( node.index, node.context );
 
-		const contextDependencies = Object.assign( {}, generator.current.contextDependencies );
+		const contextDependencies = new Map( generator.current.contextDependencies );
-		contextDependencies[ node.context ] = dependencies;
+		contextDependencies.set( node.context, dependencies );
 
 		generator.push({
 			contexts,

src/generators/server-side-rendering/visitors/Element.js

@@ -12,7 +12,7 @@ export default {
 			return meta[ node.name ].enter( generator, node );
 		}
 
-		if ( node.name in generator.components || node.name === ':Self' ) {
+		if ( generator.components.has( node.name ) || node.name === ':Self' ) {
 			Component.enter( generator, node );
 			return;
 		}
@@ -53,7 +53,7 @@ export default {
 			return;
 		}
 
-		if ( node.name in generator.components || node.name === ':Self' ) {
+		if ( generator.components.has( node.name ) || node.name === ':Self' ) {
 			Component.leave( generator, node );
 			return;
 		}

src/generators/shared/utils/counter.js

@@ -1,14 +1,17 @@
 export default function counter ( used ) {
-	const counts = {};
+	const counts = new Map();
 
-	used.forEach( name => counts[ name ] = 1 );
+	used.forEach( name => counts.set( name, 1 ) );
 
 	return function ( name ) {
-		if ( name in counts ) {
+		if ( counts.has( name ) ) {
-			return `${name}${counts[ name ]++}`;
+			const count = counts.get( name );
+			const newName = `${name}${count}`;
+			counts.set( name, count + 1 );
+			return newName;
 		}
 
-		counts[ name ] = 1;
+		counts.set( name, 1 );
 		return name;
 	};
 }

src/parse/state/tag.js

@@ -15,35 +15,34 @@ const metaTags = {
 	':Window': true
 };
 
-const specials = {
+const specials = new Map( [
-	script: {
+	[ 'script', {
 		read: readScript,
 		property: 'js'
-	},
+	} ],
-
+	[ 'style', {
-	style: {
 		read: readStyle,
 		property: 'css'
-	}
+	} ]
-};
+] );
 
 // based on http://developers.whatwg.org/syntax.html#syntax-tag-omission
-const disallowedContents = {
+const disallowedContents = new Map( [
-	li: [ 'li' ],
+	[ 'li', new Set( [ 'li' ] ) ],
-	dt: [ 'dt', 'dd' ],
+	[ 'dt', new Set( [ 'dt', 'dd' ] ) ],
-	dd: [ 'dt', 'dd' ],
+	[ 'dd', new Set( [ 'dt', 'dd' ] ) ],
-	p: 'address article aside blockquote div dl fieldset footer form h1 h2 h3 h4 h5 h6 header hgroup hr main menu nav ol p pre section table ul'.split( ' ' ),
+	[ 'p', new Set( 'address article aside blockquote div dl fieldset footer form h1 h2 h3 h4 h5 h6 header hgroup hr main menu nav ol p pre section table ul'.split( ' ' ) ) ],
-	rt: [ 'rt', 'rp' ],
+	[ 'rt', new Set( [ 'rt', 'rp' ] ) ],
-	rp: [ 'rt', 'rp' ],
+	[ 'rp', new Set( [ 'rt', 'rp' ] ) ],
-	optgroup: [ 'optgroup' ],
+	[ 'optgroup', new Set( [ 'optgroup' ] ) ],
-	option: [ 'option', 'optgroup' ],
+	[ 'option', new Set( [ 'option', 'optgroup' ] ) ],
-	thead: [ 'tbody', 'tfoot' ],
+	[ 'thead', new Set( [ 'tbody', 'tfoot' ] ) ],
-	tbody: [ 'tbody', 'tfoot' ],
+	[ 'tbody', new Set( [ 'tbody', 'tfoot' ] ) ],
-	tfoot: [ 'tbody' ],
+	[ 'tfoot', new Set( [ 'tbody' ] ) ],
-	tr: [ 'tr', 'tbody' ],
+	[ 'tr', new Set( [ 'tr', 'tbody' ] ) ],
-	td: [ 'td', 'th', 'tr' ],
+	[ 'td', new Set( [ 'td', 'th', 'tr' ] ) ],
-	th: [ 'td', 'th', 'tr' ]
+	[ 'th', new Set( [ 'td', 'th', 'tr' ] ) ],
-};
+] );
 
 function stripWhitespace ( element ) {
 	if ( element.children.length ) {
@@ -127,11 +126,10 @@ export default function tag ( parser ) {
 		parser.stack.pop();
 
 		return null;
-	} else if ( parent.name in disallowedContents ) {
+	} else if ( disallowedContents.has( parent.name ) ) {
 		// can this be a child of the parent element, or does it implicitly
 		// close it, like `<li>one<li>two`?
-		const disallowed = disallowedContents[ parent.name ];
+		if ( disallowedContents.get( parent.name ).has( name ) ) {
-		if ( ~disallowed.indexOf( name ) ) {
 			stripWhitespace( parent );
 
 			parent.end = start;
@@ -151,8 +149,8 @@ export default function tag ( parser ) {
 	parser.allowWhitespace();
 
 	// special cases – top-level <script> and <style>
-	if ( name in specials && parser.stack.length === 1 ) {
+	if ( specials.has( name ) && parser.stack.length === 1 ) {
-		const special = specials[ name ];
+		const special = specials.get( name );
 
 		if ( parser[ special.property ] ) {
 			parser.index = start;
@@ -358,4 +356,4 @@ function getShorthandValue ( start, name ) {
 			name
 		}
 	}];
-}
+}

src/validate/js/propValidators/computed.js

@@ -1,10 +1,7 @@
 import checkForDupes from '../utils/checkForDupes.js';
 import checkForComputedKeys from '../utils/checkForComputedKeys.js';
 
-const isFunctionExpression = {
+const isFunctionExpression = new Set( [ 'FunctionExpression', 'ArrowFunctionExpression' ] );
-	FunctionExpression: true,
-	ArrowFunctionExpression: true
-};
 
 export default function computed ( validator, prop ) {
 	if ( prop.value.type !== 'ObjectExpression' ) {
@@ -16,7 +13,7 @@ export default function computed ( validator, prop ) {
 	checkForComputedKeys( validator, prop.value.properties );
 
 	prop.value.properties.forEach( computation => {
-		if ( !isFunctionExpression[ computation.value.type ] ) {
+		if ( !isFunctionExpression.has( computation.value.type ) ) {
 			validator.error( `Computed properties can be function expressions or arrow function expressions`, computation.value.start );
 			return;
 		}

src/validate/js/propValidators/data.js

@@ -1,15 +1,11 @@
-const disallowed = {
+const disallowed = new Set( [ 'Literal', 'ObjectExpression', 'ArrayExpression' ] );
-	Literal: true,
-	ObjectExpression: true,
-	ArrayExpression: true
-};
 
 export default function data ( validator, prop ) {
 	while ( prop.type === 'ParenthesizedExpression' ) prop = prop.expression;
 
 	// TODO should we disallow references and expressions as well?
 
-	if ( disallowed[ prop.value.type ] ) {
+	if ( disallowed.has( prop.value.type ) ) {
 		validator.error( `'data' must be a function`, prop.value.start );
 	}
 }

src/validate/js/propValidators/methods.js

@@ -2,14 +2,7 @@ import checkForDupes from '../utils/checkForDupes.js';
 import checkForComputedKeys from '../utils/checkForComputedKeys.js';
 import usesThisOrArguments from '../utils/usesThisOrArguments.js';
 
-const builtin = {
+const builtin = new Set( [ 'set', 'get', 'on', 'fire', 'observe', 'teardown' ] );
-	set: true,
-	get: true,
-	on: true,
-	fire: true,
-	observe: true,
-	teardown: true
-};
 
 export default function methods ( validator, prop ) {
 	if ( prop.value.type !== 'ObjectExpression' ) {
@@ -21,7 +14,7 @@ export default function methods ( validator, prop ) {
 	checkForComputedKeys( validator, prop.value.properties );
 
 	prop.value.properties.forEach( prop => {
-		if ( builtin[ prop.key.name ] ) {
+		if ( builtin.has( prop.key.name ) ) {
 			validator.error( `Cannot overwrite built-in method '${prop.key.name}'` );
 		}
 

src/validate/js/utils/checkForDupes.js

@@ -1,11 +1,11 @@
 export default function checkForDupes ( validator, properties ) {
-	const seen = Object.create( null );
+	const seen = new Set();
 
 	properties.forEach( prop => {
-		if ( seen[ prop.key.name ] ) {
+		if ( seen.has( prop.key.name ) ) {
 			validator.error( `Duplicate property '${prop.key.name}'`, prop.start );
 		}
 
-		seen[ prop.key.name ] = true;
+		seen.add( prop.key.name );
 	});
 }