send delete body with content-length

index.js

@@ -87,8 +87,8 @@ function Fetch(url, opts) {
 			headers.set('content-type', 'multipart/form-data; boundary=' + options.body.getBoundary());
 		}
 
-		// bring node-fetch closer to browser behavior by setting content-length automatically for POST, PUT, PATCH requests when body is empty or string
-		if (!headers.has('content-length') && options.method.substr(0, 1).toUpperCase() === 'P') {
+		// bring node-fetch closer to browser behavior by setting content-length automatically
+		if (!headers.has('content-length') && /post|put|patch|delete/i.test(options.method)) {
 			if (typeof options.body === 'string') {
 				headers.set('content-length', Buffer.byteLength(options.body));
 			// detect form data input from form-data module, this hack avoid the need to add content-length header manually

test/test.js

@@ -715,6 +715,38 @@ describe('node-fetch', function() {
 		});
 	});
 
+	it('should allow POST request with string body', function() {
+		url = base + '/inspect';
+		opts = {
+			method: 'POST'
+			, body: 'a=1'
+		};
+		return fetch(url, opts).then(function(res) {
+			return res.json();
+		}).then(function(res) {
+			expect(res.method).to.equal('POST');
+			expect(res.body).to.equal('a=1');
+			expect(res.headers['transfer-encoding']).to.be.undefined;
+			expect(res.headers['content-length']).to.equal('3');
+		});
+	});
+
+	it('should allow DELETE request with string body', function() {
+		url = base + '/inspect';
+		opts = {
+			method: 'DELETE'
+			, body: 'a=1'
+		};
+		return fetch(url, opts).then(function(res) {
+			return res.json();
+		}).then(function(res) {
+			expect(res.method).to.equal('DELETE');
+			expect(res.body).to.equal('a=1');
+			expect(res.headers['transfer-encoding']).to.be.undefined;
+			expect(res.headers['content-length']).to.equal('3');
+		});
+	});
+
 	it('should allow PATCH request', function() {
 		url = base + '/inspect';
 		opts = {