svelte/src/compiler/compile/nodes/Attribute.ts

117 lines
2.9 KiB

import { string_literal } from '../utils/stringify';
import add_to_set from '../utils/add_to_set';
import Component from '../Component';
import Node from './shared/Node';
import Element from './Element';
import Text from './Text';
import Expression from './shared/Expression';
import TemplateScope from './shared/TemplateScope';
import { x } from 'code-red';
export default class Attribute extends Node {
type: 'Attribute' | 'Spread';
start: number;
end: number;
scope: TemplateScope;
component: Component;
parent: Element;
name: string;
is_spread: boolean;
is_true: boolean;
is_static: boolean;
expression?: Expression;
chunks: Array<Text | Expression>;
dependencies: Set<string>;
constructor(component, parent, scope, info) {
super(component, parent, scope, info);
this.scope = scope;
if (info.type === 'Spread') {
this.name = null;
this.is_spread = true;
this.is_true = false;
this.expression = new Expression(component, this, scope, info.expression);
this.dependencies = this.expression.dependencies;
this.chunks = null;
this.is_static = false;
} else {
this.name = info.name;
this.is_true = info.value === true;
this.is_static = true;
this.dependencies = new Set();
this.chunks = this.is_true
? []
: info.value.map(node => {
if (node.type === 'Text') return node;
this.is_static = false;
const expression = new Expression(component, this, scope, node.expression);
add_to_set(this.dependencies, expression.dependencies);
return expression;
});
}
}
get_dependencies() {
if (this.is_spread) return this.expression.dynamic_dependencies();
const dependencies: Set<string> = new Set();
this.chunks.forEach(chunk => {
if (chunk.type === 'Expression') {
add_to_set(dependencies, chunk.dynamic_dependencies());
}
});
return Array.from(dependencies);
}
get_value(block) {
if (this.is_true) return x`true`;
if (this.chunks.length === 0) return x`""`;
if (this.chunks.length === 1) {
return this.chunks[0].type === 'Text'
? string_literal((this.chunks[0] as Text).data)
: (this.chunks[0] as Expression).manipulate(block);
}
let expression = this.chunks
.map(chunk => chunk.type === 'Text' ? string_literal(chunk.data) : chunk.manipulate(block))
.reduce((lhs, rhs) => x`${lhs} + ${rhs}`);
if (this.chunks[0].type !== 'Text') {
expression = x`"" + ${expression}`;
}
return expression;
}
get_static_value() {
if (this.is_spread || this.dependencies.size > 0) return null;
return this.is_true
? true
: this.chunks[0]
// method should be called only when `is_static = true`
? (this.chunks[0] as Text).data
: '';
}
should_cache() {
return this.is_static
? false
: this.chunks.length === 1
// @ts-ignore todo: probably error
? this.chunks[0].node.type !== 'Identifier' || this.scope.names.has(this.chunks[0].node.name)
: true;
}
}