sheetjs/bits/31_rels.js

/* 9.3.2 OPC Relationships Markup */
var RELS = {
	WB: "http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument",
	SHEET: "http://sheetjs.openxmlformats.org/officeDocument/2006/relationships/officeDocument"
};

function parse_rels(data, currentFilePath) {
	if (!data) return data;
	if (currentFilePath.charAt(0) !== '/') {
		currentFilePath = '/'+currentFilePath;
	}
	var rels = {};
	var hash = {};
	var resolveRelativePathIntoAbsolute = function (to) {
		var toksFrom = currentFilePath.split('/');
		toksFrom.pop(); // folder path
		var toksTo = to.split('/');
		var reversed = [];
		while (toksTo.length !== 0) {
			var tokTo = toksTo.shift();
			if (tokTo === '..') {
				toksFrom.pop();
			} else if (tokTo !== '.') {
				toksFrom.push(tokTo);
			}
		}
		return toksFrom.join('/');
	};

	data.match(/<[^>]*>/g).forEach(function(x) {
		var y = parsexmltag(x);
		/* 9.3.2.2 OPC_Relationships */
		if (y[0] === '<Relationship') {
			var rel = {}; rel.Type = y.Type; rel.Target = y.Target; rel.Id = y.Id; rel.TargetMode = y.TargetMode;
			var canonictarget = y.TargetMode === 'External' ? y.Target : resolveRelativePathIntoAbsolute(y.Target);
			rels[canonictarget] = rel;
			hash[y.Id] = rel;
		}
	});
	rels["!id"] = hash;
	return rels;
}

XMLNS.RELS = 'http://schemas.openxmlformats.org/package/2006/relationships';

var RELS_ROOT = writextag('Relationships', null, {
	//'xmlns:ns0': XMLNS.RELS,
	'xmlns': XMLNS.RELS
});

/* TODO */
function write_rels(rels) {
	var o = [];
	o.push(XML_HEADER);
	o.push(RELS_ROOT);
	keys(rels['!id']).forEach(function(rid) { var rel = rels['!id'][rid];
		o.push(writextag('Relationship', null, rel));
	});
	if(o.length>2){ o.push('</Relationships>'); o[1]=o[1].replace("/>",">"); }
	return o.join("");
}