Fixes #6: don't default chunk/window size to 2 (#9)

spec.emu

@@ -10,12 +10,11 @@ copyright: false
 </pre>
 
 <emu-clause id="sec-iterator.prototype.chunks">
-  <h1>Iterator.prototype.chunks ( [ _chunkSize_ ] )</h1>
+  <h1>Iterator.prototype.chunks ( _chunkSize_ )</h1>
   <p>This method performs the following steps when called:</p>
   <emu-alg>
     1. Let _O_ be the *this* value.
     1. If _O_ is not an Object, throw a *TypeError* exception.
-    1. If _chunkSize_ is not present, set _chunkSize_ to *2*<sub>𝔽</sub>.
     1. If _chunkSize_ is not an integral Number in the inclusive interval from *1*<sub>𝔽</sub> to 𝔽(2<sup>32</sup> - 1), throw a *RangeError* exception.
     1. Let _iterated_ be ? GetIteratorDirect(_O_).
     1. Let _closure_ be a new Abstract Closure with no parameters that captures _iterated_ and _chunkSize_ and performs the following steps when called:
@@ -35,12 +34,11 @@ copyright: false
 </emu-clause>
 
 <emu-clause id="sec-iterator.prototype.windows">
-  <h1>Iterator.prototype.windows ( [ _windowSize_ ] )</h1>
+  <h1>Iterator.prototype.windows ( _windowSize_ )</h1>
   <p>This method performs the following steps when called:</p>
   <emu-alg>
     1. Let _O_ be the *this* value.
     1. If _O_ is not an Object, throw a *TypeError* exception.
-    1. If _windowSize_ is not present, set _windowSize_ to *2*<sub>𝔽</sub>.
     1. If _windowSize_ is not an integral Number in the inclusive interval from *1*<sub>𝔽</sub> to 𝔽(2<sup>32</sup> - 1), throw a *RangeError* exception.
     1. Let _iterated_ be ? GetIteratorDirect(_O_).
     1. Let _closure_ be a new Abstract Closure with no parameters that captures _iterated_ and _windowSize_ and performs the following steps when called:

src/index.ts

@@ -19,7 +19,7 @@ function* chunksImpl<A>(iter: Iterator<A>, chunkSize: number): Generator<Array<A
 }
 
 function chunks<A>(this: Iterator<A>, chunkSize: number): Generator<Array<A>>
-function chunks(this: unknown, chunkSize: unknown = 2): Generator<unknown> {
+function chunks(this: unknown, chunkSize: unknown): Generator<unknown> {
   if (
     typeof chunkSize !== 'number'
     || chunkSize <= 0
@@ -45,7 +45,7 @@ function* windowsImpl<A>(iter: Iterator<A>, windowSize: number): Generator<Array
 }
 
 function windows<A>(this: Iterator<A>, windowSize: number): Generator<Array<A>>
-function windows(this: unknown, windowSize: unknown = 2): Generator<unknown> {
+function windows(this: unknown, windowSize: unknown): Generator<unknown> {
   if (
     typeof windowSize !== 'number'
     || windowSize <= 0

test/index.mjs

@@ -12,7 +12,7 @@ function* nats(limit) {
 
 test('chunks', async t => {
   assert.deepEqual(
-    Array.from(nats(5).chunks()),
+    Array.from(nats(5).chunks(2)),
     [[0, 1], [2, 3], [4]],
   );
   assert.deepEqual(
@@ -36,6 +36,9 @@ test('chunks', async t => {
     [],
   );
 
+  assert.throws(() => {
+    nats(1).chunks();
+  }, RangeError)
   assert.throws(() => {
     nats(1).chunks([2]);
   }, RangeError)
@@ -55,7 +58,7 @@ test('chunks', async t => {
 
 test('windows', async t => {
   assert.deepEqual(
-    Array.from(nats(5).windows()),
+    Array.from(nats(5).windows(2)),
     [[0, 1], [1, 2], [2, 3], [3, 4]],
   );
   assert.deepEqual(
@@ -75,6 +78,9 @@ test('windows', async t => {
     [],
   );
 
+  assert.throws(() => {
+    nats(1).windows()
+  }, RangeError)
   assert.throws(() => {
     nats(1).windows([2]);
   }, RangeError)
@@ -90,4 +96,4 @@ test('windows', async t => {
   assert.throws(() => {
     nats(1).windows(Math.pow(2, 53));
   }, RangeError)
-});
+});