@microflash/fenceparser/src/parser.js

A metadata parser for code fences in markdown

/**
 * @typedef {Object} FenceParserOptions
 * @property {string} [rangeKey] - range key to group ranges without annotations (default: '*').
 */

import lex from "./lexer.js";

/**
 * Default configuration for FenceParser.
 * Contains default rangeKey.
 * @namespace defaults
 * @property {string} rangeKey - range key to group ranges without annotations.
 */
const defaults = {
	rangeKey: '*'
}

/**
 * Parser that converts code fence metadata string into an object.
 * @function parse
 * @param {string} input - code fence metadata string.
 * @param {FenceParserOptions} [options] - User-defined options that override defaults.
 * @returns {Object} Metadata object.
 */
export default function parse(input, options = defaults) {
	const result = {};

	if (input && input !== '{}') {
		lex(input, options?.rangeKey || defaults.rangeKey)?.forEach(token => {
			if (token.type === 'pair') {
				result[token.key] = token.value;
			} else {
				if (!result[token.key]) {
					result[token.key] = [];
				}
				token.value?.forEach(v => result[token.key].push(v));
			}
		});
	}

	return result;
}