Fix bug where isSvgMode===false in nested SVG child elements

Author: wildlyinaccurate

src/index.js

@@ -172,7 +172,8 @@ export default function renderToString(vnode, context, opts, inner, isSvgMode) {
 		for (let i=0; i<len; i++) {
 			let child = children[i];
 			if (!falsey(child)) {
-				let ret = renderToString(child, context, opts, true, nodeName==='svg');
+				let childSvgMode = nodeName==='svg' ? true : nodeName==='foreignObject' ? false : isSvgMode,
+					ret = renderToString(child, context, opts, true, childSvgMode);
 				if (!hasLarge && pretty && isLargeString(ret)) hasLarge = true;
 				pieces.push(ret);
 			}

test/render.js

@@ -73,10 +73,19 @@ describe('render', () => {
 		});
 
 		it('should render SVG elements', () => {
-			let rendered = render(<svg viewBox="0 0 360 360"><use xlinkHref="#foo"></use></svg>),
-				expected = `<svg viewBox="0 0 360 360"><use xlink:href="#foo"></use></svg>`;
-
-			expect(rendered).to.equal(expected);
+			let rendered = render((
+				<svg>
+					<image xlinkHref="#" />
+					<foreignObject>
+						<div xlinkHref="#" />
+					</foreignObject>
+					<g>
+						<image xlinkHref="#" />
+					</g>
+				</svg>
+			));
+
+			expect(rendered).to.equal(`<svg><image xlink:href="#"></image><foreignObject><div xlinkHref="#"></div></foreignObject><g><image xlink:href="#"></image></g></svg>`);
 		});
 	});