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 4038x 4038x 4038x 4038x 4038x 4038x 4038x 4038x 4038x 4038x 4038x 4038x 4038x 4038x 4038x 2x 2x 2x 2x 2x 2x 2x 11461x 11461x 11461x 11461x 11461x 11461x 11461x 11461x 11461x 11461x 11461x 11456x 11456x 11456x 11456x 2x 2x 2x 2x 2x 2x 2x 15499x 15499x 15499x 15499x 15499x 15499x 15499x 15499x 15499x 15499x 15499x 15499x 15499x 15499x 15499x 15499x 15499x 15499x 15499x 227x 4x 4x 4x 4x 4x 4x 4x 4x 4x 227x 227x 15499x 15499x 15499x 15499x 15494x 122x 122x 122x 3966x 3966x 3966x 167x 167x 167x 3966x 3966x 3966x 3966x 2207x 2207x 2207x 60x 60x 2207x 3966x 122x 15494x 15499x 15499x 2x 2x 2x 2x 2x 2x 246x 246x 246x 1495x 1495x 1495x 1495x 1495x 1495x 3x 3x 3x 3x 3x 3x 1495x 1495x 1495x 246x 246x  
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();
		}
	});
}