svelte/src/generators/dom/visitors/Element/Element.ts

365 lines
10 KiB

import deindent from '../../../../utils/deindent';
import visit from '../../visit';
import visitSlot from '../Slot';
import visitComponent from '../Component';
import visitWindow from './meta/Window';
import visitAttribute from './Attribute';
import addBindings from './addBindings';
import flattenReference from '../../../../utils/flattenReference';
import validCalleeObjects from '../../../../utils/validCalleeObjects';
import * as namespaces from '../../../../utils/namespaces';
import getStaticAttributeValue from '../../../../utils/getStaticAttributeValue';
import isVoidElementName from '../../../../utils/isVoidElementName';
import addTransitions from './addTransitions';
import { DomGenerator } from '../../index';
import Block from '../../Block';
import { Node } from '../../../../interfaces';
import { State } from '../../interfaces';
import reservedNames from '../../../../utils/reservedNames';
import { stringify } from '../../../../utils/stringify';
const meta: Record<string, any> = {
':Window': visitWindow,
};
export default function visitElement(
generator: DomGenerator,
block: Block,
state: State,
node: Node,
elementStack: Node[],
componentStack: Node[]
) {
if (node.name in meta) {
return meta[node.name](generator, block, node);
}
if (node.name === 'slot') {
if (generator.customElement) {
const slotName = getStaticAttributeValue(node, 'name') || 'default';
generator.slots.add(slotName);
} else {
return visitSlot(generator, block, state, node, elementStack, componentStack);
}
}
if (generator.components.has(node.name) || node.name === ':Self' || node.name === ':Switch') {
return visitComponent(generator, block, state, node, elementStack, componentStack);
}
const childState = node._state;
const name = childState.parentNode;
const slot = node.attributes.find((attribute: Node) => attribute.name === 'slot');
const parentNode = node.slotted ?
`${componentStack[componentStack.length - 1].var}._slotted.${slot.value[0].data}` : // TODO this looks bonkers
state.parentNode;
block.addVariable(name);
block.builders.create.addLine(
`${name} = ${getRenderStatement(
generator,
childState.namespace,
node.name
)};`
);
if (generator.hydratable) {
block.builders.claim.addBlock(deindent`
${name} = ${getClaimStatement(generator, childState.namespace, state.parentNodes, node)};
var ${childState.parentNodes} = @children(${name});
`);
}
if (parentNode) {
block.builders.mount.addLine(
`@appendNode(${name}, ${parentNode});`
);
} else {
block.builders.mount.addLine(`@insertNode(${name}, #target, anchor);`);
// TODO we eventually need to consider what happens to elements
// that belong to the same outgroup as an outroing element...
block.builders.unmount.addLine(`@detachNode(${name});`);
}
// add CSS encapsulation attribute
if (node._needsCssAttribute && !generator.customElement) {
generator.needsEncapsulateHelper = true;
block.builders.hydrate.addLine(
`@encapsulateStyles(${name});`
);
if (node._cssRefAttribute) {
block.builders.hydrate.addLine(
`@setAttribute(${name}, "svelte-ref-${node._cssRefAttribute}", "");`
)
}
}
if (node.name === 'textarea') {
// this is an egregious hack, but it's the easiest way to get <textarea>
// children treated the same way as a value attribute
if (node.children.length > 0) {
node.attributes.push({
type: 'Attribute',
name: 'value',
value: node.children,
});
node.children = [];
}
}
// insert static children with textContent or innerHTML
if (!childState.namespace && node.canUseInnerHTML && node.children.length > 0) {
if (node.children.length === 1 && node.children[0].type === 'Text') {
block.builders.create.addLine(
`${name}.textContent = ${stringify(node.children[0].data)};`
);
} else {
block.builders.create.addLine(
`${name}.innerHTML = ${stringify(node.children.map(toHTML).join(''))};`
);
}
} else {
node.children.forEach((child: Node) => {
visit(generator, block, childState, child, elementStack.concat(node), componentStack);
});
}
addBindings(generator, block, childState, node);
node.attributes.filter((a: Node) => a.type === 'Attribute').forEach((attribute: Node) => {
visitAttribute(generator, block, childState, node, attribute);
});
// event handlers
node.attributes.filter((a: Node) => a.type === 'EventHandler').forEach((attribute: Node) => {
const isCustomEvent = generator.events.has(attribute.name);
const shouldHoist = !isCustomEvent && state.inEachBlock;
const context = shouldHoist ? null : name;
const usedContexts: string[] = [];
if (attribute.expression) {
generator.addSourcemapLocations(attribute.expression);
const flattened = flattenReference(attribute.expression.callee);
if (!validCalleeObjects.has(flattened.name)) {
// allow event.stopPropagation(), this.select() etc
// TODO verify that it's a valid callee (i.e. built-in or declared method)
generator.code.prependRight(
attribute.expression.start,
`${block.alias('component')}.`
);
if (shouldHoist) childState.usesComponent = true; // this feels a bit hacky but it works!
}
attribute.expression.arguments.forEach((arg: Node) => {
const { contexts } = block.contextualise(arg, context, true);
contexts.forEach(context => {
if (!~usedContexts.indexOf(context)) usedContexts.push(context);
if (!~childState.allUsedContexts.indexOf(context))
childState.allUsedContexts.push(context);
});
});
}
const _this = context || 'this';
const declarations = usedContexts.map(name => {
if (name === 'state') {
if (shouldHoist) childState.usesComponent = true;
return `var state = ${block.alias('component')}.get();`;
}
const listName = block.listNames.get(name);
const indexName = block.indexNames.get(name);
const contextName = block.contexts.get(name);
return `var ${listName} = ${_this}._svelte.${listName}, ${indexName} = ${_this}._svelte.${indexName}, ${contextName} = ${listName}[${indexName}];`;
});
// get a name for the event handler that is globally unique
// if hoisted, locally unique otherwise
const handlerName = (shouldHoist ? generator : block).getUniqueName(
`${attribute.name.replace(/[^a-zA-Z0-9_$]/g, '_')}_handler`
);
// create the handler body
const handlerBody = deindent`
${childState.usesComponent &&
`var ${block.alias('component')} = ${_this}._svelte.component;`}
${declarations}
${attribute.expression ?
`[✂${attribute.expression.start}-${attribute.expression.end}✂];` :
`${block.alias('component')}.fire("${attribute.name}", event);`}
`;
if (isCustomEvent) {
block.addVariable(handlerName);
block.builders.hydrate.addBlock(deindent`
${handlerName} = %events-${attribute.name}.call(#component, ${name}, function(event) {
${handlerBody}
});
`);
block.builders.destroy.addLine(deindent`
${handlerName}.teardown();
`);
} else {
const handler = deindent`
function ${handlerName}(event) {
${handlerBody}
}
`;
if (shouldHoist) {
generator.blocks.push(handler);
} else {
block.builders.init.addBlock(handler);
}
block.builders.hydrate.addLine(
`@addListener(${name}, "${attribute.name}", ${handlerName});`
);
block.builders.destroy.addLine(
`@removeListener(${name}, "${attribute.name}", ${handlerName});`
);
}
});
// refs
node.attributes.filter((a: Node) => a.type === 'Ref').forEach((attribute: Node) => {
const ref = `#component.refs.${attribute.name}`;
block.builders.mount.addLine(
`${ref} = ${name};`
);
block.builders.destroy.addLine(
`if (${ref} === ${name}) ${ref} = null;`
);
generator.usesRefs = true; // so component.refs object is created
});
addTransitions(generator, block, childState, node);
if (childState.allUsedContexts.length || childState.usesComponent) {
const initialProps: string[] = [];
const updates: string[] = [];
if (childState.usesComponent) {
initialProps.push(`component: #component`);
}
childState.allUsedContexts.forEach((contextName: string) => {
if (contextName === 'state') return;
const listName = block.listNames.get(contextName);
const indexName = block.indexNames.get(contextName);
initialProps.push(
`${listName}: ${listName},\n${indexName}: ${indexName}`
);
updates.push(
`${name}._svelte.${listName} = ${listName};\n${name}._svelte.${indexName} = ${indexName};`
);
});
if (initialProps.length) {
block.builders.hydrate.addBlock(deindent`
${name}._svelte = {
${initialProps.join(',\n')}
};
`);
}
if (updates.length) {
block.builders.update.addBlock(updates.join('\n'));
}
}
if (node.initialUpdate) {
block.builders.mount.addBlock(node.initialUpdate);
}
block.builders.claim.addLine(
`${childState.parentNodes}.forEach(@detachNode);`
);
function toHTML(node: Node) {
if (node.type === 'Text') return node.data;
let open = `<${node.name}`;
if (node._needsCssAttribute) {
open += ` ${generator.stylesheet.id}`;
}
if (node._cssRefAttribute) {
open += ` svelte-ref-${node._cssRefAttribute}`;
}
node.attributes.forEach((attr: Node) => {
open += ` ${attr.name}${stringifyAttributeValue(attr.value)}`
});
if (isVoidElementName(node.name)) return open + '>';
return `${open}>${node.children.map(toHTML).join('')}</${node.name}>`;
}
}
function getRenderStatement(
generator: DomGenerator,
namespace: string,
name: string
) {
if (namespace === 'http://www.w3.org/2000/svg') {
return `@createSvgElement("${name}")`;
}
if (namespace) {
return `document.createElementNS("${namespace}", "${name}")`;
}
return `@createElement("${name}")`;
}
function getClaimStatement(
generator: DomGenerator,
namespace: string,
nodes: string,
node: Node
) {
const attributes = node.attributes
.filter((attr: Node) => attr.type === 'Attribute')
.map((attr: Node) => `${quoteProp(attr.name, generator.legacy)}: true`)
.join(', ');
const name = namespace ? node.name : node.name.toUpperCase();
return `@claimElement(${nodes}, "${name}", ${attributes
? `{ ${attributes} }`
: `{}`}, ${namespace === namespaces.svg ? true : false})`;
}
function quoteProp(name: string, legacy: boolean) {
const isLegacyPropName = legacy && reservedNames.has(name);
if (/[^a-zA-Z_$0-9]/.test(name) || isLegacyPropName) return `"${name}"`;
return name;
}
function stringifyAttributeValue(value: Node | true) {
if (value === true) return '';
if (value.length === 0) return `=""`;
const data = value[0].data;
return `=${JSON.stringify(data)}`;
}