mirror of https://github.com/sveltejs/svelte
dry {#each}/{#await} destructuring (#4596)
Tan Li Hau
5 years ago
committed by
GitHub
parent
c743e72a1e
commit
37cc5888f8
@ -0,0 +1,58 @@
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import { x } from 'code-red';
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import { Node, Identifier, RestElement, Property } from 'estree';
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export interface Context {
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key: Identifier;
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name?: string;
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modifier: (node: Node) => Node;
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}
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export function unpack_destructuring(contexts: Context[], node: Node, modifier: (node: Node) => Node) {
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if (!node) return;
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if (node.type === 'Identifier') {
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contexts.push({
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key: node as Identifier,
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modifier
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});
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} else if (node.type === 'RestElement') {
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contexts.push({
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key: node.argument as Identifier,
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modifier
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});
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} else if (node.type === 'ArrayPattern') {
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node.elements.forEach((element, i) => {
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if (element && element.type === 'RestElement') {
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unpack_destructuring(contexts, element, node => x`${modifier(node)}.slice(${i})` as Node);
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} else if (element && element.type === 'AssignmentPattern') {
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unpack_destructuring(contexts, element.left, node => x`${modifier(node)}[${i}] !== undefined ? ${modifier(node)}[${i}] : ${element.right}` as Node);
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} else {
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unpack_destructuring(contexts, element, node => x`${modifier(node)}[${i}]` as Node);
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}
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});
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} else if (node.type === 'ObjectPattern') {
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const used_properties = [];
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node.properties.forEach((property) => {
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const props: (RestElement | Property) = (property as any);
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if (props.type === 'RestElement') {
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unpack_destructuring(
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contexts,
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props.argument,
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node => x`@object_without_properties(${modifier(node)}, [${used_properties}])` as Node
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);
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} else {
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const key = property.key as Identifier;
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const value = property.value;
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used_properties.push(x`"${(key as Identifier).name}"`);
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if (value.type === 'AssignmentPattern') {
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unpack_destructuring(contexts, value.left, node => x`${modifier(node)}.${key.name} !== undefined ? ${modifier(node)}.${key.name} : ${value.right}` as Node);
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} else {
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unpack_destructuring(contexts, value, node => x`${modifier(node)}.${key.name}` as Node);
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}
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}
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});
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}
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}
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@ -1,35 +0,0 @@
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import { Pattern, Identifier, RestElement } from "estree";
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import { Node } from "acorn";
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export default function traverse_destructure_pattern(
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node: Pattern,
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callback: (node: Identifier, parent: Node, key: string | number) => void
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) {
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function traverse(node: Pattern, parent, key) {
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switch (node.type) {
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case "Identifier":
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return callback(node, parent, key);
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case "ArrayPattern":
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for (let i = 0; i < node.elements.length; i++) {
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const element = node.elements[i];
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traverse(element, node.elements, i);
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}
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break;
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case "ObjectPattern":
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for (let i = 0; i < node.properties.length; i++) {
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const property = node.properties[i];
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if (property.type === "Property") {
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traverse(property.value, property, "value");
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} else {
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traverse((property as any) as RestElement, node.properties, i);
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}
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}
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break;
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case "RestElement":
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return traverse(node.argument, node, 'argument');
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case "AssignmentPattern":
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return traverse(node.left, node, 'left');
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}
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}
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traverse(node, null, null);
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}
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@ -1,202 +1,82 @@
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import { Parser } from '../index';
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import { reserved } from '../../utils/names';
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interface Identifier {
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start: number;
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end: number;
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type: 'Identifier';
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name: string;
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}
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interface Property {
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start: number;
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end: number;
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type: 'Property';
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kind: 'init' | 'rest';
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shorthand: boolean;
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key: Identifier;
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value: Context;
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}
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interface Context {
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start: number;
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end: number;
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type: 'Identifier' | 'ArrayPattern' | 'ObjectPattern' | 'RestIdentifier';
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name?: string;
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elements?: Context[];
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properties?: Property[];
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}
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function error_on_assignment_pattern(parser: Parser) {
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if (parser.eat('=')) {
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parser.error({
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code: 'invalid-assignment-pattern',
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message: 'Assignment patterns are not supported'
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}, parser.index - 1);
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}
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}
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function error_on_rest_pattern_not_last(parser: Parser) {
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parser.error({
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code: 'rest-pattern-not-last',
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message: 'Rest destructuring expected to be last'
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}, parser.index);
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}
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export default function read_context(parser: Parser) {
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const context: Context = {
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start: parser.index,
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end: null,
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type: null
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};
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if (parser.eat('[')) {
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context.type = 'ArrayPattern';
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context.elements = [];
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do {
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parser.allow_whitespace();
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const lastContext = context.elements[context.elements.length - 1];
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if (lastContext && lastContext.type === 'RestIdentifier') {
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error_on_rest_pattern_not_last(parser);
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}
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if (parser.template[parser.index] === ',') {
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context.elements.push(null);
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} else {
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context.elements.push(read_context(parser));
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parser.allow_whitespace();
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}
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} while (parser.eat(','));
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error_on_assignment_pattern(parser);
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parser.eat(']', true);
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context.end = parser.index;
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}
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else if (parser.eat('{')) {
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context.type = 'ObjectPattern';
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context.properties = [];
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do {
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parser.allow_whitespace();
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if (parser.eat('...')) {
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parser.allow_whitespace();
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import { Parser } from "../index";
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import { isIdentifierStart } from "acorn";
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import full_char_code_at from "../../utils/full_char_code_at";
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import {
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is_bracket_open,
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is_bracket_close,
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is_bracket_pair,
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get_bracket_close
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} from "../utils/bracket";
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import { parse_expression_at } from "../acorn";
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import { Pattern } from "estree";
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export default function read_context(
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parser: Parser
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): Pattern & { start: number; end: number } {
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const start = parser.index;
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const name = parser.read_identifier();
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const key: Identifier = {
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start,
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end: parser.index,
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type: 'Identifier',
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name
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};
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const property: Property = {
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start,
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end: parser.index,
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type: 'Property',
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kind: 'rest',
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shorthand: true,
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key,
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value: key
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};
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context.properties.push(property);
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parser.allow_whitespace();
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if (parser.eat(',')) {
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parser.error({
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code: `comma-after-rest`,
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message: `Comma is not permitted after the rest element`
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}, parser.index - 1);
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}
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let i = parser.index;
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break;
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}
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// TODO: DRY this out somehow
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// We don't know whether we want to allow reserved words until we see whether there's a ':' after it
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// Probably ideally we'd use Acorn to do all of this
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const start = parser.index;
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const name = parser.read_identifier(true);
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const key: Identifier = {
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const code = full_char_code_at(parser.template, i);
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if (isIdentifierStart(code, true)) {
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return {
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type: "Identifier",
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name: parser.read_identifier(),
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start,
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end: parser.index,
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type: 'Identifier',
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name
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end: parser.index
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};
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parser.allow_whitespace();
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let value: Context;
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if (parser.eat(':')) {
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parser.allow_whitespace();
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value = read_context(parser);
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} else {
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if (reserved.has(name)) {
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parser.error({
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code: `unexpected-reserved-word`,
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message: `'${name}' is a reserved word in JavaScript and cannot be used here`
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}, start);
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}
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value = key;
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}
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const property: Property = {
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start,
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end: value.end,
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type: 'Property',
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kind: 'init',
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shorthand: value.type === 'Identifier' && value.name === name,
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key,
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value
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};
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context.properties.push(property);
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parser.allow_whitespace();
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} while (parser.eat(','));
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error_on_assignment_pattern(parser);
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parser.eat('}', true);
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context.end = parser.index;
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if (!is_bracket_open(code)) {
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parser.error({
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code: "unexpected-token",
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message: "Expected identifier or destructure pattern"
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});
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}
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else if (parser.eat('...')) {
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const name = parser.read_identifier();
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if (name) {
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context.type = 'RestIdentifier';
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context.end = parser.index;
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context.name = name;
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}
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const bracket_stack = [code];
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i += code <= 0xffff ? 1 : 2;
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else {
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while (i < parser.template.length) {
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const code = full_char_code_at(parser.template, i);
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if (is_bracket_open(code)) {
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bracket_stack.push(code);
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} else if (is_bracket_close(code)) {
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if (!is_bracket_pair(bracket_stack[bracket_stack.length - 1], code)) {
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parser.error({
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code: 'invalid-context',
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message: 'Expected a rest pattern'
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code: "unexpected-token",
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message: `Expected ${String.fromCharCode(
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get_bracket_close(bracket_stack[bracket_stack.length - 1])
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)}`
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});
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}
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bracket_stack.pop();
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if (bracket_stack.length === 0) {
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i += code <= 0xffff ? 1 : 2;
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break;
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}
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else {
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const name = parser.read_identifier();
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if (name) {
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context.type = 'Identifier';
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context.end = parser.index;
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context.name = name;
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}
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else {
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parser.error({
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code: 'invalid-context',
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message: 'Expected a name, array pattern or object pattern'
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});
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i += code <= 0xffff ? 1 : 2;
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}
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error_on_assignment_pattern(parser);
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parser.index = i;
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const pattern_string = parser.template.slice(start, i);
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try {
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// the length of the `space_with_newline` has to be start - 1
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// because we added a `(` in front of the pattern_string,
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// which shifted the entire string to right by 1
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// so we offset it by removing 1 character in the `space_with_newline`
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// to achieve that, we remove the 1st space encountered,
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// so it will not affect the `column` of the node
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let space_with_newline = parser.template.slice(0, start).replace(/[^\n]/g, ' ');
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const first_space = space_with_newline.indexOf(' ');
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space_with_newline = space_with_newline.slice(0, first_space) + space_with_newline.slice(first_space + 1);
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return (parse_expression_at(
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`${space_with_newline}(${pattern_string} = 1)`,
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start - 1
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) as any).left;
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} catch (error) {
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parser.acorn_error(error);
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}
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return context;
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}
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@ -1,3 +1,7 @@
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<script>
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export let animals;
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</script>
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{#each animals as [key, value, ...rest]}
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<p>{key}: {value}</p>
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{/each}
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@ -0,0 +1,7 @@
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<script>
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export let animalEntries;
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</script>
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{#each animalEntries as { animal, species = 'unknown', kilogram: weight = 50 , ...props } }
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<p {...props}>{animal} - {species} - {weight}kg</p>
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{/each}
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