All files / src/compiler/preprocess index.js

98.65% Statements 368/373
86.88% Branches 53/61
93.33% Functions 14/15
98.64% Lines 364/369

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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 3702x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 135x 135x 135x 135x 135x 78x 78x 135x 66x 66x 135x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 2x 2x 2x 2x 2x 2x 2x 65x 65x 65x 65x 65x 65x 65x 65x 40x 40x 40x 39x 39x 39x 35x 35x 39x 40x 65x 65x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x       2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 65x 63x 63x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 65x 2x 2x 2x 2x 2x 2x 69x 69x 69x 69x 69x 69x 69x 21x 21x 21x 21x 69x 69x 69x 2x 2x 2x 2x 65x 65x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 66x 66x 66x 66x 66x 66x 66x 66x 66x 66x 66x 66x 66x 66x 66x 75x 75x 75x 69x 75x 75x 75x 75x 75x 75x 75x 75x 65x 65x 65x 65x 75x 75x 75x 75x 66x 66x 66x 2x 2x 2x 2x 2x 16x 16x 16x 16x 16x 16x 16x 16x 16x 16x 12x 12x 12x 16x 16x 16x 16x     16x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 53x 68x 16x 16x 16x 68x 28x 28x 28x 68x 38x 38x 38x 68x 53x 53x 53x  
/** @import { Processed, Preprocessor, MarkupPreprocessor, PreprocessorGroup } from './public.js' */
/** @import { SourceUpdate, Source } from './private.js' */
/** @import { DecodedSourceMap, RawSourceMap } from '@ampproject/remapping' */
import { getLocator } from 'locate-character';
import {
	MappedCode,
	parse_attached_sourcemap,
	sourcemap_add_offset,
	combine_sourcemaps,
	get_basename
} from '../utils/mapped_code.js';
import { decode_map } from './decode_sourcemap.js';
import { replace_in_code, slice_source } from './replace_in_code.js';
 
/**
 * Represents intermediate states of the preprocessing.
 * Implements the Source interface.
 */
class PreprocessResult {
	/** @type {string} */
	source;
 
	/** @type {string | undefined} The filename passed as-is to preprocess */
	filename;
 
	// sourcemap_list is sorted in reverse order from last map (index 0) to first map (index -1)
	// so we use sourcemap_list.unshift() to add new maps
	// https://github.com/ampproject/remapping#multiple-transformations-of-a-file
 
	/**
	 * @default []
	 * @type {Array<DecodedSourceMap | RawSourceMap>}
	 */
	sourcemap_list = [];
 
	/**
	 * @default []
	 * @type {string[]}
	 */
	dependencies = [];
 
	/**
	 * @type {string | null} last part of the filename, as used for `sources` in sourcemaps
	 */
	file_basename = /** @type {any} */ (undefined);
 
	/**
	 * @type {ReturnType<typeof getLocator>}
	 */
	get_location = /** @type {any} */ (undefined);
 
	/**
	 * @param {string} source
	 * @param {string} [filename]
	 */
	constructor(source, filename) {
		this.source = source;
		this.filename = filename;
		this.update_source({ string: source });
		// preprocess source must be relative to itself or equal null
		this.file_basename = filename == null ? null : get_basename(filename);
	}
 
	/**
	 * @param {SourceUpdate} opts
	 */
	update_source({ string: source, map, dependencies }) {
		if (source != null) {
			this.source = source;
			this.get_location = getLocator(source);
		}
		if (map) {
			this.sourcemap_list.unshift(map);
		}
		if (dependencies) {
			this.dependencies.push(...dependencies);
		}
	}
 
	/**
	 * @returns {Processed}
	 */
	to_processed() {
		// Combine all the source maps for each preprocessor function into one
		// @ts-expect-error TODO there might be a bug in hiding here
		const map = combine_sourcemaps(this.file_basename, this.sourcemap_list);
		return {
			// TODO return separated output, in future version where svelte.compile supports it:
			// style: { code: styleCode, map: styleMap },
			// script { code: scriptCode, map: scriptMap },
			// markup { code: markupCode, map: markupMap },
			code: this.source,
			dependencies: [...new Set(this.dependencies)],
			// @ts-expect-error TODO there might be a bug in hiding here
			map,
			toString: () => this.source
		};
	}
}
/**
 * Convert preprocessor output for the tag content into MappedCode
 * @param {Processed} processed
 * @param {{ line: number; column: number; }} location
 * @param {string} file_basename
 * @returns {MappedCode}
 */
function processed_content_to_code(processed, location, file_basename) {
	// Convert the preprocessed code and its sourcemap to a MappedCode
 
	/**
	 * @type {DecodedSourceMap | undefined}
	 */
	let decoded_map = undefined;
	if (processed.map) {
		decoded_map = decode_map(processed);
		// decoded map may not have sources for empty maps like `{ mappings: '' }`
		if (decoded_map?.sources) {
			// offset only segments pointing at original component source
			const source_index = decoded_map.sources.indexOf(file_basename);
			if (source_index !== -1) {
				sourcemap_add_offset(decoded_map, location, source_index);
			}
		}
	}
	return MappedCode.from_processed(processed.code, decoded_map);
}
/**
 * Given the whole tag including content, return a `MappedCode`
 * representing the tag content replaced with `processed`.
 * @param {Processed} processed
 * @param {'style' | 'script'} tag_name
 * @param {string} original_attributes
 * @param {string} generated_attributes
 * @param {Source} source
 * @returns {MappedCode}
 */
function processed_tag_to_code(
	processed,
	tag_name,
	original_attributes,
	generated_attributes,
	source
) {
	const { file_basename, get_location } = source;
 
	/**
	 * @param {string} code
	 * @param {number} offset
	 */
	const build_mapped_code = (code, offset) =>
		MappedCode.from_source(slice_source(code, offset, source));
 
	// To map the open/close tag and content starts positions correctly, we need to
	// differentiate between the original attributes and the generated attributes:
	// `source` contains the original attributes and its get_location maps accordingly.
	const original_tag_open = `<${tag_name}${original_attributes}>`;
	const tag_open = `<${tag_name}${generated_attributes}>`;
	/** @type {MappedCode} */
	let tag_open_code;
 
	if (original_tag_open.length !== tag_open.length) {
		// Generate a source map for the open tag
		/** @type {DecodedSourceMap['mappings']} */
		const mappings = [
			[
				// start of tag
				[0, 0, 0, 0],
				// end of tag start
				[`<${tag_name}`.length, 0, 0, `<${tag_name}`.length]
			]
		];
 
		const line = tag_open.split('\n').length - 1;
		const column = tag_open.length - (line === 0 ? 0 : tag_open.lastIndexOf('\n')) - 1;
 
		while (mappings.length <= line) {
			// end of tag start again, if this is a multi line mapping
			mappings.push([[0, 0, 0, `<${tag_name}`.length]]);
		}
 
		// end of tag
		mappings[line].push([
			column,
			0,
			original_tag_open.split('\n').length - 1,
			original_tag_open.length - original_tag_open.lastIndexOf('\n') - 1
		]);
 
		/** @type {DecodedSourceMap} */
		const map = {
			version: 3,
			names: [],
			sources: [file_basename],
			mappings
		};
		sourcemap_add_offset(map, get_location(0), 0);
		tag_open_code = MappedCode.from_processed(tag_open, map);
	} else {
		tag_open_code = build_mapped_code(tag_open, 0);
	}
 
	const tag_close = `</${tag_name}>`;
	const tag_close_code = build_mapped_code(
		tag_close,
		original_tag_open.length + source.source.length
	);
 
	parse_attached_sourcemap(processed, tag_name);
	const content_code = processed_content_to_code(
		processed,
		get_location(original_tag_open.length),
		file_basename
	);
 
	return tag_open_code.concat(content_code).concat(tag_close_code);
}
 
const attribute_pattern = /([\w-$]+\b)(?:=(?:"([^"]*)"|'([^']*)'|(\S+)))?/g;
 
/**
 * @param {string} str
 */
function parse_tag_attributes(str) {
	/** @type {Record<string, string | boolean>} */
	const attrs = {};
 
	/** @type {RegExpMatchArray | null} */
	let match;
	while ((match = attribute_pattern.exec(str)) !== null) {
		const name = match[1];
		const value = match[2] || match[3] || match[4];
		attrs[name] = !value || value;
	}
 
	return attrs;
}
 
/**
 * @param {Record<string, string | boolean> | undefined} attributes
 */
function stringify_tag_attributes(attributes) {
	if (!attributes) return;
 
	let value = Object.entries(attributes)
		.map(([key, value]) => (value === true ? key : `${key}="${value}"`))
		.join(' ');
	if (value) {
		value = ' ' + value;
	}
	return value;
}
 
const regex_style_tags =
	/<!--[^]*?-->|<style((?:\s+[^=>'"/\s]+=(?:"[^"]*"|'[^']*'|[^>\s]+)|\s+[^=>'"/\s]+)*\s*)(?:\/>|>([\S\s]*?)<\/style>)/g;
const regex_script_tags =
	/<!--[^]*?-->|<script((?:\s+[^=>'"/\s]+=(?:"[^"]*"|'[^']*'|[^>\s]+)|\s+[^=>'"/\s]+)*\s*)(?:\/>|>([\S\s]*?)<\/script>)/g;
 
/**
 * Calculate the updates required to process all instances of the specified tag.
 * @param {'style' | 'script'} tag_name
 * @param {Preprocessor} preprocessor
 * @param {Source} source
 * @returns {Promise<SourceUpdate>}
 */
async function process_tag(tag_name, preprocessor, source) {
	const { filename, source: markup } = source;
	const tag_regex = tag_name === 'style' ? regex_style_tags : regex_script_tags;
 
	/**
	 * @type {string[]}
	 */
	const dependencies = [];
 
	/**
	 * @param {string} tag_with_content
	 * @param {number} tag_offset
	 * @returns {Promise<MappedCode>}
	 */
	async function process_single_tag(tag_with_content, attributes = '', content = '', tag_offset) {
		const no_change = () =>
			MappedCode.from_source(slice_source(tag_with_content, tag_offset, source));
		if (!attributes && !content) return no_change();
		const processed = await preprocessor({
			content: content || '',
			attributes: parse_tag_attributes(attributes || ''),
			markup,
			filename
		});
		if (!processed) return no_change();
		if (processed.dependencies) dependencies.push(...processed.dependencies);
		if (!processed.map && processed.code === content) return no_change();
		return processed_tag_to_code(
			processed,
			tag_name,
			attributes,
			stringify_tag_attributes(processed.attributes) ?? attributes,
			slice_source(content, tag_offset, source)
		);
	}
	const { string, map } = await replace_in_code(tag_regex, process_single_tag, source);
	return { string, map, dependencies };
}
 
/**
 * @param {MarkupPreprocessor} process
 * @param {Source} source
 */
async function process_markup(process, source) {
	const processed = await process({
		content: source.source,
		filename: source.filename
	});
	if (processed) {
		return {
			string: processed.code,
			map: processed.map
				? // TODO: can we use decode_sourcemap?
					typeof processed.map === 'string'
					? JSON.parse(processed.map)
					: processed.map
				: undefined,
			dependencies: processed.dependencies
		};
	} else {
		return {};
	}
}
 
/**
 * The preprocess function provides convenient hooks for arbitrarily transforming component source code.
 * For example, it can be used to convert a <style lang="sass"> block into vanilla CSS.
 *
 * https://svelte.dev/docs/svelte-compiler#svelte-preprocess
 * @param {string} source
 * @param {PreprocessorGroup | PreprocessorGroup[]} preprocessor
 * @param {{ filename?: string }} [options]
 * @returns {Promise<Processed>}
 */
export default async function preprocess(source, preprocessor, options) {
	/**
	 * @type {string | undefined}
	 */
	const filename = (options && options.filename) || /** @type {any} */ (preprocessor).filename; // legacy
	const preprocessors = preprocessor
		? Array.isArray(preprocessor)
			? preprocessor
			: [preprocessor]
		: [];
	const result = new PreprocessResult(source, filename);
 
	// TODO keep track: what preprocessor generated what sourcemap?
	// to make debugging easier = detect low-resolution sourcemaps in fn combine_mappings
	for (const preprocessor of preprocessors) {
		if (preprocessor.markup) {
			// @ts-expect-error TODO there might be a bug in hiding here
			result.update_source(await process_markup(preprocessor.markup, result));
		}
		if (preprocessor.script) {
			// @ts-expect-error TODO there might be a bug in hiding here
			result.update_source(await process_tag('script', preprocessor.script, result));
		}
		if (preprocessor.style) {
			// @ts-expect-error TODO there might be a bug in hiding here
			result.update_source(await process_tag('style', preprocessor.style, result));
		}
	}
 
	return result.to_processed();
}