Throw when a GET/HEAD Request is created with body

As mandated by the spec

src/request.js

@@ -38,17 +38,24 @@ export default class Request extends Body {
 			parsedURL = parse_url(input.url);
 		}
 
+		let method = init.method || input.method || 'GET';
+
+		if ((init.body != null || input instanceof Request && input.body != null) &&
+			(method === 'GET' || method === 'HEAD')) {
+			throw new TypeError('Request with GET/HEAD method cannot have body');
+		}
+
 		super(init.body || clone(input), {
 			timeout: init.timeout || input.timeout || 0,
 			size: init.size || input.size || 0
 		});
 
 		// fetch spec options
-		this.method = init.method || input.method || 'GET';
+		this.method = method;
 		this.redirect = init.redirect || input.redirect || 'follow';
 		this.headers = new Headers(init.headers || input.headers || {});
 
-		if (init.body) {
+		if (init.body != null) {
 			const contentType = extractContentType(this);
 			if (contentType && !this.headers.has('Content-Type')) {
 				this.headers.append('Content-Type', contentType);

test/test.js

@@ -1444,6 +1444,17 @@ describe(`node-fetch with FOLLOW_SPEC = ${defaultFollowSpec}`, () => {
 		});
 	});
 
+	it('should throw error with GET/HEAD requests with body', function() {
+		expect(() => new Request('.', { body: '' }))
+			.to.throw(TypeError);
+		expect(() => new Request('.', { body: 'a' }))
+			.to.throw(TypeError);
+		expect(() => new Request('.', { body: '', method: 'HEAD' }))
+			.to.throw(TypeError);
+		expect(() => new Request('.', { body: 'a', method: 'HEAD' }))
+			.to.throw(TypeError);
+	});
+
 	it('should support empty options in Response constructor', function() {
 		let body = resumer().queue('a=1').end();
 		body = body.pipe(new stream.PassThrough());
@@ -1557,6 +1568,7 @@ describe(`node-fetch with FOLLOW_SPEC = ${defaultFollowSpec}`, () => {
 	it('should support arrayBuffer() method in Request constructor', function() {
 		url = base;
 		var req = new Request(url, {
+			method: 'POST',
 			body: 'a=1'
 		});
 		expect(req.url).to.equal(url);
@@ -1570,6 +1582,7 @@ describe(`node-fetch with FOLLOW_SPEC = ${defaultFollowSpec}`, () => {
 	it('should support text() method in Request constructor', function() {
 		url = base;
 		const req = new Request(url, {
+			method: 'POST',
 			body: 'a=1'
 		});
 		expect(req.url).to.equal(url);
@@ -1581,6 +1594,7 @@ describe(`node-fetch with FOLLOW_SPEC = ${defaultFollowSpec}`, () => {
 	it('should support json() method in Request constructor', function() {
 		url = base;
 		const req = new Request(url, {
+			method: 'POST',
 			body: '{"a":1}'
 		});
 		expect(req.url).to.equal(url);
@@ -1592,6 +1606,7 @@ describe(`node-fetch with FOLLOW_SPEC = ${defaultFollowSpec}`, () => {
 	it('should support buffer() method in Request constructor', function() {
 		url = base;
 		const req = new Request(url, {
+			method: 'POST',
 			body: 'a=1'
 		});
 		expect(req.url).to.equal(url);