docxtemplater/es6/tests/xml-prettify.js

.docx generator working with templates and data (like Mustache)

/* eslint-disable complexity */

const reg = /(>)\s*(<)(\/*)/g;
const wsexp = / *(.*) +\n/g;
const contexp = /(<.+>)(.+\n)/g;

module.exports = function (xml) {
	xml = xml.replace(reg, "$1\n$2$3").replace(wsexp, "$1\n").replace(contexp, "$1\n$2");
	let formatted = "";
	const lines = xml.split("\n");
	let indent = 0;
	let lastType = "other";
	// 4 types of tags - single, closing, opening, other (text, doctype, comment) - 4*4 = 16 transitions
	const transitions = {
		"single->single": 0,
		"single->closing": -1,
		"single->opening": 0,
		"single->other": 0,
		"closing->single": 0,
		"closing->closing": -1,
		"closing->opening": 0,
		"closing->other": 0,
		"opening->single": 1,
		"opening->closing": 0,
		"opening->opening": 1,
		"opening->other": 1,
		"other->single": 0,
		"other->closing": -1,
		"other->opening": 0,
		"other->other": 0,
	};

	for (let i = 0; i < lines.length; i++) {
		const ln = lines[i];
		const single = Boolean(ln.match(/<.+\/>/)); // is this line a single tag? ex. <br />
		const closing = Boolean(ln.match(/<\/.+>/)); // is this a closing tag? ex. </a>
		const opening = Boolean(ln.match(/<[^!].*>/)); // is this even a tag (that's not <!something>)
		const type = single ? "single" : closing ? "closing" : opening ? "opening" : "other";
		const fromTo = lastType + "->" + type;
		lastType = type;
		let padding = "";

		indent += transitions[fromTo];
		for (let j = 0; j < indent; j++) {
			padding += "\t";
		}
		if (fromTo === "opening->closing") {
			// substr removes line break (\n) from prev loop
			formatted = formatted.substr(0, formatted.length - 1) + ln + "\n";
		}
		else {
			formatted += padding + ln + "\n";
		}
	}

	return formatted;
};