prism-command-line.js

(function () {

	if (typeof Prism === 'undefined' || typeof document === 'undefined') {
		return;
	}

	var CLASS_PATTERN = /(?:^|\s)command-line(?:\s|$)/;
	var PROMPT_CLASS = 'command-line-prompt';

	/** @type {(str: string, prefix: string) => boolean} */
	var startsWith = ''.startsWith
		? function (s, p) { return s.startsWith(p); }
		: function (s, p) { return s.indexOf(p) === 0; };

	/**
	 * Repeats the given string some number of times.
	 *
	 * This is just a polyfill for `String.prototype.repeat`.
	 *
	 * @param {string} str
	 * @param {number} times
	 * @returns {string}
	 */
	function repeat(str, times) {
		var s = '';
		for (var i = 0; i < times; i++) {
			s += str;
		}
		return s;
	}

	/**
	 * Returns whether the given hook environment has a command line info object.
	 *
	 * @param {any} env
	 * @returns {boolean}
	 */
	function hasCommandLineInfo(env) {
		var vars = env.vars = env.vars || {};
		return 'command-line' in vars;
	}
	/**
	 * Returns the command line info object from the given hook environment.
	 *
	 * @param {any} env
	 * @returns {CommandLineInfo}
	 *
	 * @typedef CommandLineInfo
	 * @property {boolean} [complete]
	 * @property {number} [numberOfLines]
	 * @property {string[]} [outputLines]
	 */
	function getCommandLineInfo(env) {
		var vars = env.vars = env.vars || {};
		return vars['command-line'] = vars['command-line'] || {};
	}


	Prism.hooks.add('before-highlight', function (env) {
		var commandLine = getCommandLineInfo(env);

		if (commandLine.complete || !env.code) {
			commandLine.complete = true;
			return;
		}

		// Works only for <code> wrapped inside <pre> (not inline).
		var pre = env.element.parentElement;
		if (!pre || !/pre/i.test(pre.nodeName) || // Abort only if neither the <pre> nor the <code> have the class
			(!CLASS_PATTERN.test(pre.className) && !CLASS_PATTERN.test(env.element.className))) {
			commandLine.complete = true;
			return;
		}

		// The element might be highlighted multiple times, so we just remove the previous prompt
		var existingPrompt = env.element.querySelector('.' + PROMPT_CLASS);
		if (existingPrompt) {
			existingPrompt.remove();
		}

		var codeLines = env.code.split('\n');
		commandLine.numberOfLines = codeLines.length;
		/** @type {string[]} */
		var outputLines = commandLine.outputLines = [];

		var outputSections = pre.getAttribute('data-output');
		var outputFilter = pre.getAttribute('data-filter-output');
		if (outputSections !== null) { // The user specified the output lines. -- cwells
			outputSections.split(',').forEach(function (section) {
				var range = section.split('-');
				var outputStart = parseInt(range[0], 10);
				var outputEnd = range.length === 2 ? parseInt(range[1], 10) : outputStart;

				if (!isNaN(outputStart) && !isNaN(outputEnd)) {
					if (outputStart < 1) {
						outputStart = 1;
					}
					if (outputEnd > codeLines.length) {
						outputEnd = codeLines.length;
					}
					// Convert start and end to 0-based to simplify the arrays. -- cwells
					outputStart--;
					outputEnd--;
					// Save the output line in an array and clear it in the code so it's not highlighted. -- cwells
					for (var j = outputStart; j <= outputEnd; j++) {
						outputLines[j] = codeLines[j];
						codeLines[j] = '';
					}
				}
			});
		} else if (outputFilter) { // Treat lines beginning with this string as output. -- cwells
			for (var i = 0; i < codeLines.length; i++) {
				if (startsWith(codeLines[i], outputFilter)) { // This line is output. -- cwells
					outputLines[i] = codeLines[i].slice(outputFilter.length);
					codeLines[i] = '';
				}
			}
		}

		env.code = codeLines.join('\n');
	});

	Prism.hooks.add('before-insert', function (env) {
		var commandLine = getCommandLineInfo(env);

		if (commandLine.complete) {
			return;
		}

		// Reinsert the output lines into the highlighted code. -- cwells
		var codeLines = env.highlightedCode.split('\n');
		var outputLines = commandLine.outputLines || [];
		for (var i = 0, l = outputLines.length; i < l; i++) {
			if (outputLines.hasOwnProperty(i)) {
				codeLines[i] = outputLines[i];
			}
		}
		env.highlightedCode = codeLines.join('\n');
	});

	Prism.hooks.add('complete', function (env) {
		if (!hasCommandLineInfo(env)) {
			// the previous hooks never ran
			return;
		}

		var commandLine = getCommandLineInfo(env);

		if (commandLine.complete) {
			return;
		}

		var pre = env.element.parentElement;
		if (CLASS_PATTERN.test(env.element.className)) { // Remove the class "command-line" from the <code>
			env.element.className = env.element.className.replace(CLASS_PATTERN, ' ');
		}
		if (!CLASS_PATTERN.test(pre.className)) { // Add the class "command-line" to the <pre>
			pre.className += ' command-line';
		}

		function getAttribute(key, defaultValue) {
			return (pre.getAttribute(key) || defaultValue).replace(/"/g, '&quot');
		}

		// Create the "rows" that will become the command-line prompts. -- cwells
		var promptLines;
		var rowCount = commandLine.numberOfLines || 0;
		var promptText = getAttribute('data-prompt', '');
		if (promptText !== '') {
			promptLines = repeat('<span data-prompt="' + promptText + '"></span>', rowCount);
		} else {
			var user = getAttribute('data-user', 'user');
			var host = getAttribute('data-host', 'localhost');
			promptLines = repeat('<span data-user="' + user + '" data-host="' + host + '"></span>', rowCount);
		}

		// Create the wrapper element. -- cwells
		var prompt = document.createElement('span');
		prompt.className = PROMPT_CLASS;
		prompt.innerHTML = promptLines;

		// Remove the prompt from the output lines. -- cwells
		var outputLines = commandLine.outputLines || [];
		for (var i = 0, l = outputLines.length; i < l; i++) {
			if (outputLines.hasOwnProperty(i)) {
				var node = prompt.children[i];
				node.removeAttribute('data-user');
				node.removeAttribute('data-host');
				node.removeAttribute('data-prompt');
			}
		}

		env.element.insertBefore(prompt, env.element.firstChild);
		commandLine.complete = true;
	});

}());