Add markdown format support (#25)

Co-authored-by: Dawid Dziurla <dawidd0811@gmail.com>

node_modules/string-width/index.js

@@ -0,0 +1,39 @@
+'use strict';
+const stripAnsi = require('strip-ansi');
+const isFullwidthCodePoint = require('is-fullwidth-code-point');
+const emojiRegex = require('emoji-regex')();
+
+module.exports = input => {
+	input = input.replace(emojiRegex, '  ');
+
+	if (typeof input !== 'string' || input.length === 0) {
+		return 0;
+	}
+
+	input = stripAnsi(input);
+
+	let width = 0;
+
+	for (let i = 0; i < input.length; i++) {
+		const code = input.codePointAt(i);
+
+		// Ignore control characters
+		if (code <= 0x1F || (code >= 0x7F && code <= 0x9F)) {
+			continue;
+		}
+
+		// Ignore combining characters
+		if (code >= 0x300 && code <= 0x36F) {
+			continue;
+		}
+
+		// Surrogates
+		if (code > 0xFFFF) {
+			i++;
+		}
+
+		width += isFullwidthCodePoint(code) ? 2 : 1;
+	}
+
+	return width;
+};