All files / src/compiler/phases/1-parse acorn.js

100% Statements 144/144
96.55% Branches 28/29
100% Functions 8/8
100% Lines 141/141

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 1422x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 4087x 4087x 4087x 4087x 4087x 4087x 4087x 4087x 4087x 4087x 4087x 4087x 4087x 4087x 4087x 2x 2x 2x 2x 2x 2x 2x 11606x 11606x 11606x 11606x 11606x 11606x 11606x 11606x 11606x 11606x 11606x 11601x 11601x 11601x 11601x 2x 2x 2x 2x 2x 2x 2x 15693x 15693x 15693x 15693x 15693x 15693x 15693x 15693x 15693x 15693x 15693x 15693x 15693x 15693x 15693x 15693x 15693x 15693x 15693x 228x 4x 4x 4x 4x 4x 4x 4x 4x 4x 228x 228x 15693x 15693x 15693x 15693x 15688x 122x 122x 122x 3976x 3976x 3976x 168x 168x 168x 3976x 3976x 3976x 3976x 2220x 2220x 2220x 60x 60x 2220x 3976x 122x 15688x 15693x 15693x 2x 2x 2x 2x 2x 2x 256x 256x 256x 1587x 1587x 1587x 1587x 1587x 1587x 3x 3x 3x 3x 3x 3x 1587x 1587x 1587x 256x 256x  
import * as acorn from 'acorn';
import { walk } from 'zimmerframe';
import { tsPlugin } from 'acorn-typescript';
 
const ParserWithTS = acorn.Parser.extend(tsPlugin({ allowSatisfies: true }));
 
/**
 * @param {string} source
 * @param {boolean} typescript
 */
export function parse(source, typescript) {
	const parser = typescript ? ParserWithTS : acorn.Parser;
	const { onComment, add_comments } = get_comment_handlers(source);
 
	const ast = parser.parse(source, {
		onComment,
		sourceType: 'module',
		ecmaVersion: 13,
		locations: true
	});
 
	if (typescript) amend(source, ast);
	add_comments(ast);
 
	return /** @type {import('estree').Program} */ (ast);
}
 
/**
 * @param {string} source
 * @param {boolean} typescript
 * @param {number} index
 */
export function parse_expression_at(source, typescript, index) {
	const parser = typescript ? ParserWithTS : acorn.Parser;
	const { onComment, add_comments } = get_comment_handlers(source);
 
	const ast = parser.parseExpressionAt(source, index, {
		onComment,
		sourceType: 'module',
		ecmaVersion: 13,
		locations: true
	});
 
	if (typescript) amend(source, ast);
	add_comments(ast);
 
	return ast;
}
 
/**
 * Acorn doesn't add comments to the AST by itself. This factory returns the capabilities
 * to add them after the fact. They are needed in order to support `svelte-ignore` comments
 * in JS code and so that `prettier-plugin-svelte` doesn't remove all comments when formatting.
 * @param {string} source
 */
function get_comment_handlers(source) {
	/**
	 * @typedef {import('estree').Comment & {
	 *   start: number;
	 *   end: number;
	 * }} CommentWithLocation
	 */
 
	/** @type {CommentWithLocation[]} */
	const comments = [];
 
	return {
		/**
		 * @param {boolean} block
		 * @param {string} value
		 * @param {number} start
		 * @param {number} end
		 */
		onComment: (block, value, start, end) => {
			if (block && /\n/.test(value)) {
				let a = start;
				while (a > 0 && source[a - 1] !== '\n') a -= 1;
 
				let b = a;
				while (/[ \t]/.test(source[b])) b += 1;
 
				const indentation = source.slice(a, b);
				value = value.replace(new RegExp(`^${indentation}`, 'gm'), '');
			}
 
			comments.push({ type: block ? 'Block' : 'Line', value, start, end });
		},
 
		/** @param {acorn.Node & { leadingComments?: CommentWithLocation[]; trailingComments?: CommentWithLocation[]; }} ast */
		add_comments(ast) {
			if (comments.length === 0) return;
 
			walk(ast, null, {
				_(node, { next }) {
					let comment;
 
					while (comments[0] && comments[0].start < node.start) {
						comment = /** @type {CommentWithLocation} */ (comments.shift());
						(node.leadingComments ||= []).push(comment);
					}
 
					next();
 
					if (comments[0]) {
						const slice = source.slice(node.end, comments[0].start);
 
						if (/^[,) \t]*$/.test(slice)) {
							node.trailingComments = [/** @type {CommentWithLocation} */ (comments.shift())];
						}
					}
				}
			});
		}
	};
}
 
/**
 * Tidy up some stuff left behind by acorn-typescript
 * @param {string} source
 * @param {import('acorn').Node} node
 */
function amend(source, node) {
	return walk(node, null, {
		_(node, context) {
			// @ts-expect-error
			delete node.loc.start.index;
			// @ts-expect-error
			delete node.loc.end.index;
 
			if (/** @type {any} */ (node).typeAnnotation && node.end === undefined) {
				// i think there might be a bug in acorn-typescript that prevents
				// `end` from being assigned when there's a type annotation
				let end = /** @type {any} */ (node).typeAnnotation.start;
				while (/\s/.test(source[end - 1])) end -= 1;
				node.end = end;
			}
 
			context.next();
		}
	});
}