refactor response create function outside of promise handler

not sure that this is favorable or not but thought that it might be and it allows
for easier testing of the creation of responses and their properties.

Author: jkalis-rm

.gitignore

@@ -3,3 +3,4 @@ node_modules
 npm-debug.log
 .DS_Store
 /polyfill/index.js
+coverage

src/index.mjs

@@ -1,37 +1,36 @@
+const regex = /^(.*?):[^\S\n]*([\s\S]*?)$/gm;
+const response = (request, headers) => ({
+	ok: (request.status/100|0) == 2,		// 200-299
+	statusText: request.statusText,
+	status: request.status,
+	url: request.responseURL,
+	text: () => Promise.resolve(request.responseText),
+	json: () => Promise.resolve(JSON.parse(request.responseText)),
+	blob: () => Promise.resolve(new Blob([request.response])),
+	clone: () => response(request, headers),
+	headers: {
+		keys: () => headers.keys,
+		entries: () => headers.all,
+		get: n => headers.raw[n.toLowerCase()],
+		has: n => n.toLowerCase() in headers.raw
+	}
+});
+
 export default function(url, options) {
 	options = options || {};
 	return new Promise( (resolve, reject) => {
 		const request = new XMLHttpRequest();
-		const keys = [];
-		const all = [];
-		const headers = {};
-
-		const response = () => ({
-			ok: (request.status/100|0) == 2,		// 200-299
-			statusText: request.statusText,
-			status: request.status,
-			url: request.responseURL,
-			text: () => Promise.resolve(request.responseText),
-			json: () => Promise.resolve(JSON.parse(request.responseText)),
-			blob: () => Promise.resolve(new Blob([request.response])),
-			clone: response,
-			headers: {
-				keys: () => keys,
-				entries: () => all,
-				get: n => headers[n.toLowerCase()],
-				has: n => n.toLowerCase() in headers
-			}
-		});
 
 		request.open(options.method || 'get', url, true);
 
 		request.onload = () => {
-			request.getAllResponseHeaders().replace(/^(.*?):[^\S\n]*([\s\S]*?)$/gm, (m, key, value) => {
-				keys.push(key = key.toLowerCase());
-				all.push([key, value]);
-				headers[key] = headers[key] ? `${headers[key]},${value}` : value;
+			const head = { all: [], keys: [], raw: {} };
+			request.getAllResponseHeaders().replace(regex, (m, key, value) => {
+				head.all.push([key, value]);
+				head.keys.push(key = key.toLowerCase());
+				head.raw[key] = head.raw[key] ? `${head.raw[key]},${value}` : value;
 			});
-			resolve(response());
+			resolve(response(request, head));
 		};
 
 		request.onerror = reject;
@@ -45,3 +44,5 @@ export default function(url, options) {
 		request.send(options.body || null);
 	});
 }
+
+export { response };

test/index.js

@@ -1,4 +1,4 @@
-import fetch from '../src/index.mjs';
+import fetch, { response } from '../src/index.mjs';
 import fetchDist from '..';
 
 describe('unfetch', () => {
@@ -81,4 +81,33 @@ describe('unfetch', () => {
 			return p;
 		});
 	});
+
+	describe('response()', () => {
+		it('returns text()', () => response({ responseText: 'A passing test.' })
+			.text()
+			.then((text) => expect(text).toBe('A passing test.'))
+		);
+
+		it('returns blob()', () => response({ response: 'A passing test.' })
+			.blob()
+			.then((text) => expect(text.toString()).toBe(new Blob(['A passing test.']).toString()))
+		);
+
+		it('returns headers', () => {
+			const all = [['x-foo', 'bar'], ['x-baz', 'boo']];
+			const result = response({}, { all }).headers.entries();
+			expect(result).toEqual(all);
+		});
+
+		it('returns header keys', () => {
+			const result = response({}, { keys: ['x-foo'] }).headers.keys();
+			expect(result).toEqual(['x-foo']);
+		});
+
+		it('returns headers has', () => {
+			const raw = { 'x-foo': 'bar', 'x-baz': 'boo' };
+			const test = response({}, { raw }).headers;
+			expect(test.has('x-foo')).toBe(true);
+		});
+	});
 });