Fix falsey and boolean attributes so they render properly in HTML and XML modes

Author: developit

src/index.js

@@ -140,7 +140,15 @@ export default function renderToString(vnode, context, opts, inner) {
 			if (name==='dangerouslySetInnerHTML') {
 				html = v && v.__html;
 			}
-			else if (!falsey(v) && typeof v!=='function') {
+			else if ((v || v===0) && typeof v!=='function') {
+				if (v===true) {
+					v = name;
+					// in non-xml mode, allow boolean attributes
+					if (!opts || !opts.xml) {
+						s += ' ' + name;
+						continue;
+					}
+				}
 				s += ` ${name}="${encodeEntities(v)}"`;
 			}
 		}

test/render.js

@@ -19,6 +19,15 @@ describe('render', () => {
 				expected = `<div></div>`;
 
 			expect(rendered).to.equal(expected);
+
+			expect(render(<div foo={0} />)).to.equal(`<div foo="0"></div>`)
+		});
+
+		it('should collapse collapsible attributes', () => {
+			let rendered = render(<div class="" style="" foo={true} bar />),
+				expected = `<div foo bar></div>`;
+
+			expect(rendered).to.equal(expected);
 		});
 
 		it('should omit functions', () => {
@@ -254,4 +263,22 @@ describe('render', () => {
 			expect(rendered).to.equal('<div a="a" b="b" b1="b1" c="c"></div>');
 		});
 	});
+
+	describe('xml:true', () => {
+		let renderXml = jsx => render(jsx, null, { xml:true });
+
+		it('should render end-tags', () => {
+			expect(renderXml(<div />)).to.equal(`<div />`);
+			expect(renderXml(<a />)).to.equal(`<a />`);
+			expect(renderXml(<a>b</a>)).to.equal(`<a>b</a>`);
+		});
+
+		it('should render boolean attributes with named values', () => {
+			expect(renderXml(<div foo bar />)).to.equal(`<div foo="foo" bar="bar" />`);
+		});
+
+		it('should exclude falsey attributes', () => {
+			expect(renderXml(<div foo={false} bar={0} />)).to.equal(`<div bar="0" />`);
+		});
+	});
 });