Allow usage of iterable object in Blob constructor. (#108)

* Allow usage of iterable object in Blob constructor.

* Fix ESLint errors

Author: octet-stream

index.js

@@ -58,9 +58,10 @@ const _Blob = class Blob {
 	 * @param {{ type?: string }} [options]
 	 */
 	constructor(blobParts = [], options = {}) {
+		const parts = [];
 		let size = 0;
 
-		const parts = blobParts.map(element => {
+		for (const element of blobParts) {
 			let part;
 			if (ArrayBuffer.isView(element)) {
 				part = new Uint8Array(element.buffer.slice(element.byteOffset, element.byteOffset + element.byteLength));
@@ -73,8 +74,8 @@ const _Blob = class Blob {
 			}
 
 			size += ArrayBuffer.isView(part) ? part.byteLength : part.size;
-			return part;
-		});
+			parts.push(part);
+		}
 
 		const type = options.type === undefined ? '' : String(options.type);
 

test.js

@@ -36,6 +36,41 @@ test('Blob ctor parts', async t => {
 	t.is(await blob.text(), 'abcdefg[object Object]foo=');
 });
 
+test('Blob ctor threats an object with @@iterator as a sequence', async t => {
+	const blob = new Blob({[Symbol.iterator]: Array.prototype[Symbol.iterator]});
+
+	t.is(blob.size, 0);
+	t.is(await blob.text(), '');
+});
+
+test('Blob ctor reads blob parts from object with @@iterator', async t => {
+	const input = ['one', 'two', 'three'];
+	const expected = input.join('');
+
+	const blob = new Blob({
+		* [Symbol.iterator]() {
+			yield * input;
+		}
+	});
+
+	t.is(blob.size, new TextEncoder().encode(expected).byteLength);
+	t.is(await blob.text(), expected);
+});
+
+test('Blob ctor threats a string as a sequence', async t => {
+	const expected = 'abc';
+	const blob = new Blob(expected);
+
+	t.is(await blob.text(), expected);
+});
+
+test('Blob ctor threats Uint8Array as a sequence', async t => {
+	const input = [1, 2, 3];
+	const blob = new Blob(new Uint8Array(input));
+
+	t.is(await blob.text(), input.join(''));
+});
+
 test('Blob size', t => {
 	const data = 'a=1';
 	const blob = new Blob([data]);