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8.9 KiB

import Binding from '../../../nodes/Binding';
import ElementWrapper from '../Element';
import get_object from '../../../utils/get_object';
import Block from '../../Block';
import Node from '../../../nodes/shared/Node';
import Renderer from '../../Renderer';
import flatten_reference from '../../../utils/flatten_reference';
import EachBlock from '../../../nodes/EachBlock';
import { Node as INode } from '../../../../interfaces';
function get_tail(node: INode) {
const end = node.end;
while (node.type === 'MemberExpression') node = node.object;
return { start: node.end, end };
}
export default class BindingWrapper {
node: Binding;
parent: ElementWrapper;
object: string;
handler: {
uses_context: boolean;
mutation: string;
contextual_dependencies: Set<string>;
snippet?: string;
};
snippet: string;
is_readonly: boolean;
needs_lock: boolean;
constructor(block: Block, node: Binding, parent: ElementWrapper) {
this.node = node;
this.parent = parent;
const { dependencies } = this.node.expression;
block.add_dependencies(dependencies);
// TODO does this also apply to e.g. `<input type='checkbox' bind:group='foo'>`?
if (parent.node.name === 'select') {
parent.select_binding_dependencies = dependencies;
dependencies.forEach((prop: string) => {
parent.renderer.component.indirect_dependencies.set(prop, new Set());
});
}
if (node.is_contextual) {
// we need to ensure that the each block creates a context including
// the list and the index, if they're not otherwise referenced
const { name } = get_object(this.node.expression.node);
const each_block = this.parent.node.scope.get_owner(name);
(each_block as EachBlock).has_binding = true;
}
this.object = get_object(this.node.expression.node).name;
// TODO unfortunate code is necessary because we need to use `ctx`
// inside the fragment, but not inside the <script>
const contextless_snippet = this.parent.renderer.component.source.slice(this.node.expression.node.start, this.node.expression.node.end);
// view to model
this.handler = get_event_handler(this, parent.renderer, block, this.object, contextless_snippet);
this.snippet = this.node.expression.render(block);
this.is_readonly = this.node.is_readonly;
this.needs_lock = this.node.name === 'currentTime'; // TODO others?
}
get_dependencies() {
const dependencies = new Set(this.node.expression.dependencies);
this.node.expression.dependencies.forEach((prop: string) => {
const indirect_dependencies = this.parent.renderer.component.indirect_dependencies.get(prop);
if (indirect_dependencies) {
indirect_dependencies.forEach(indirect_dependency => {
dependencies.add(indirect_dependency);
});
}
});
return dependencies;
}
is_readonly_media_attribute() {
return this.node.is_readonly_media_attribute();
}
render(block: Block, lock: string) {
if (this.is_readonly) return;
const { parent } = this;
const update_conditions: string[] = this.needs_lock ? [`!${lock}`] : [];
const dependency_array = [...this.node.expression.dependencies];
if (dependency_array.length === 1) {
update_conditions.push(`changed.${dependency_array[0]}`);
} else if (dependency_array.length > 1) {
update_conditions.push(
`(${dependency_array.map(prop => `changed.${prop}`).join(' || ')})`
);
}
if (parent.node.name === 'input') {
const type = parent.node.get_static_attribute_value('type');
if (type === null || type === "" || type === "text") {
update_conditions.push(`(${parent.var}.${this.node.name} !== ${this.snippet})`);
}
}
// model to view
let update_dom = get_dom_updater(parent, this);
// special cases
switch (this.node.name) {
case 'group':
{
const binding_group = get_binding_group(parent.renderer, this.node.expression.node);
block.builders.hydrate.add_line(
`ctx.$$binding_groups[${binding_group}].push(${parent.var});`
);
block.builders.destroy.add_line(
`ctx.$$binding_groups[${binding_group}].splice(ctx.$$binding_groups[${binding_group}].indexOf(${parent.var}), 1);`
);
break;
}
case 'currentTime':
case 'playbackRate':
case 'volume':
update_conditions.push(`!@_isNaN(${this.snippet})`);
break;
case 'paused':
{
// this is necessary to prevent audio restarting by itself
const last = block.get_unique_name(`${parent.var}_is_paused`);
block.add_variable(last, 'true');
update_conditions.push(`${last} !== (${last} = ${this.snippet})`);
update_dom = `${parent.var}[${last} ? "pause" : "play"]();`;
break;
}
case 'value':
if (parent.node.get_static_attribute_value('type') === 'file') {
update_dom = null;
}
}
if (update_dom) {
block.builders.update.add_line(
update_conditions.length ? `if (${update_conditions.join(' && ')}) ${update_dom}` : update_dom
);
}
if (!/(currentTime|paused)/.test(this.node.name)) {
block.builders.mount.add_block(update_dom);
}
}
}
function get_dom_updater(
element: ElementWrapper,
binding: BindingWrapper
) {
const { node } = element;
if (binding.is_readonly_media_attribute()) {
return null;
}
if (binding.node.name === 'this') {
return null;
}
if (node.name === 'select') {
return node.get_static_attribute_value('multiple') === true ?
`@select_options(${element.var}, ${binding.snippet})` :
`@select_option(${element.var}, ${binding.snippet})`;
}
if (binding.node.name === 'group') {
const type = node.get_static_attribute_value('type');
const condition = type === 'checkbox'
? `~${binding.snippet}.indexOf(${element.var}.__value)`
: `${element.var}.__value === ${binding.snippet}`;
return `${element.var}.checked = ${condition};`;
}
if (binding.node.name === 'text') {
return `if (${binding.snippet} !== ${element.var}.textContent) ${element.var}.textContent = ${binding.snippet};`;
}
if (binding.node.name === 'html') {
return `if (${binding.snippet} !== ${element.var}.innerHTML) ${element.var}.innerHTML = ${binding.snippet};`;
}
return `${element.var}.${binding.node.name} = ${binding.snippet};`;
}
function get_binding_group(renderer: Renderer, value: Node) {
const { parts } = flatten_reference(value); // TODO handle cases involving computed member expressions
const keypath = parts.join('.');
// TODO handle contextual bindings — `keypath` should include unique ID of
// each block that provides context
let index = renderer.binding_groups.indexOf(keypath);
if (index === -1) {
index = renderer.binding_groups.length;
renderer.binding_groups.push(keypath);
}
return index;
}
function mutate_store(store, value, tail) {
return tail
? `${store}.update($$value => ($$value${tail} = ${value}, $$value));`
: `${store}.set(${value});`;
}
function get_event_handler(
binding: BindingWrapper,
renderer: Renderer,
block: Block,
name: string,
snippet: string
) {
const value = get_value_from_dom(renderer, binding.parent, binding);
const store = binding.object[0] === '$' ? binding.object.slice(1) : null;
let tail = '';
if (binding.node.expression.node.type === 'MemberExpression') {
const { start, end } = get_tail(binding.node.expression.node);
tail = renderer.component.source.slice(start, end);
}
if (binding.node.is_contextual) {
const { object, property, snippet } = block.bindings.get(name);
return {
uses_context: true,
mutation: store
? mutate_store(store, value, tail)
: `${snippet}${tail} = ${value};`,
contextual_dependencies: new Set([object, property])
};
}
const mutation = store
? mutate_store(store, value, tail)
: `${snippet} = ${value};`;
if (binding.node.expression.node.type === 'MemberExpression') {
return {
uses_context: binding.node.expression.uses_context,
mutation,
contextual_dependencies: binding.node.expression.contextual_dependencies,
snippet
};
}
return {
uses_context: false,
mutation,
contextual_dependencies: new Set()
};
}
function get_value_from_dom(
renderer: Renderer,
element: ElementWrapper,
binding: BindingWrapper
) {
const { node } = element;
const { name } = binding.node;
if (name === 'this') {
return `$$node`;
}
// <select bind:value='selected>
if (node.name === 'select') {
return node.get_static_attribute_value('multiple') === true ?
`@select_multiple_value(this)` :
`@select_value(this)`;
}
const type = node.get_static_attribute_value('type');
// <input type='checkbox' bind:group='foo'>
if (name === 'group') {
const binding_group = get_binding_group(renderer, binding.node.expression.node);
if (type === 'checkbox') {
return `@get_binding_group_value($$binding_groups[${binding_group}])`;
}
return `this.__value`;
}
// <input type='range|number' bind:value>
if (type === 'range' || type === 'number') {
return `@to_number(this.${name})`;
}
if ((name === 'buffered' || name === 'seekable' || name === 'played')) {
return `@time_ranges_to_array(this.${name})`;
}
if (name === 'text') {
return `this.textContent`;
}
if (name === 'html') {
return `this.innerHTML`;
}
// everything else
return `this.${name}`;
}