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

52 lines
1.3 KiB

import Node from './shared/Node';
import Component from '../Component';
import { walk } from 'estree-walker';
import { BasePattern, Identifier } from 'estree';
import TemplateScope from './shared/TemplateScope';
import { TemplateNode } from '../../interfaces';
import compiler_errors from '../compiler_errors';
const applicable = new Set(['Identifier', 'ObjectExpression', 'ArrayExpression', 'Property']);
export default class Let extends Node {
type: 'Let';
name: Identifier;
value: Identifier;
names: string[] = [];
constructor(component: Component, parent: Node, scope: TemplateScope, info: TemplateNode) {
super(component, parent, scope, info);
this.name = { type: 'Identifier', name: info.name };
const { names } = this;
if (info.expression) {
this.value = info.expression;
walk(info.expression, {
enter(node: Identifier|BasePattern) {
if (!applicable.has(node.type)) {
return component.error(node as any, compiler_errors.invalid_let);
}
if (node.type === 'Identifier') {
names.push((node as Identifier).name);
}
// slightly unfortunate hack
if (node.type === 'ArrayExpression') {
node.type = 'ArrayPattern';
}
if (node.type === 'ObjectExpression') {
node.type = 'ObjectPattern';
}
}
});
} else {
names.push(this.name.name);
}
}
}