♻️ refactor: Use default exports everywhere.

Fix some function signatures, remove some circular dependencies.

src/base/StopIteration.js

@@ -2,4 +2,4 @@
  * Error thrown by {@link next} when the input iterator is exhausted.
  * @class
  */
-export {StopIteration} from '@aureooms/js-error';
+export {StopIteration as default} from '@aureooms/js-error';

src/base/_count.js

@@ -12,9 +12,9 @@
  *
  * @param {Number} start - The starting value.
  * @param {Number} step - The step between the values.
- * @returns {Iterator}
+ * @returns {IterableIterator}
  */
-export function* _count(start, step) {
+export default function* _count(start, step) {
 	while (true) {
 		yield start;
 

src/base/_drop.js

@@ -0,0 +1,21 @@
+import assert from 'assert';
+import iter from './iter.js';
+import consume from './consume.js';
+
+/**
+ * Drops the first <code>n</code> values of the input iterable.
+ *
+ * @example
+ * // returns [ 3 , 4 ]
+ * list( _drop( range( 5 ) , 3 ) ) ;
+ *
+ * @param {Iterable} iterable - The input iterable.
+ * @param {Number} n - The nonnegative number of values to drop.
+ * @returns {IterableIterator} - The remaining values of the input iterable.
+ */
+export default function* _drop(iterable, n) {
+	assert(Number.isInteger(n) && n >= 0);
+	const iterator = iter(iterable);
+	consume(iterator, n);
+	yield* iterator;
+}

src/base/_next.js

@@ -4,6 +4,6 @@
  * @param {Iterator} iterator - The input iterator.
  * @returns {{done: Boolean, value: Object}}
  */
-export function _next(iterator) {
+export default function _next(iterator) {
 	return iterator.next();
 }

src/base/_range.js

@@ -6,9 +6,9 @@
  * @param {Number} start - The starting value.
  * @param {Number} stop - The stopping value.
  * @param {Number} step - The step value.
- * @returns {Iterator}
+ * @returns {IterableIterator}
  */
-export function* _range(start, stop, step) {
+export default function* _range(start, stop, step) {
 	if (step < 0) {
 		for (; start > stop; start += step) {
 			yield start;

src/base/_tail.js

@@ -0,0 +1,18 @@
+import assert from 'assert';
+import deque from '@aureooms/js-collections-deque';
+
+/**
+ * Returns the last <code>n</code> values of the input iterable in an array.
+ *
+ * @example
+ * // returns [ 3 , 4 ]
+ * list( _tail( range( 5 ) , 2 ) ) ;
+ *
+ * @param {Iterable} iterable - The input iterable.
+ * @param {Number} n - The nonnegative number of values to include in the output.
+ * @returns {IterableIterator} - The last <code>n</code> values of the input iterable.
+ */
+export default function* _tail(iterable, n) {
+	assert(Number.isInteger(n) && n >= 0);
+	yield* deque(iterable, n);
+}

src/base/_take.js

@@ -0,0 +1,29 @@
+import assert from 'assert';
+import iter from './iter.js';
+
+/**
+ * Yields the first <code>n</code> elements of the input iterable.
+ *
+ * @example
+ * // returns [ 0 , 1 , 2 ]
+ * list( _take( range( 5 ) , 3 ) ) ;
+ *
+ * @param {Iterable} iterable - The input iterable.
+ * @param {Number} n - The nonnegative number of elements to include in the output.
+ * @returns {IterableIterator} - The first <code>n</code> elements of the input iterable.
+ */
+export default function* _take(iterable, n) {
+	assert(Number.isInteger(n) && n >= 0);
+
+	const iterator = iter(iterable);
+
+	while (n-- > 0) {
+		const current = iterator.next();
+
+		if (current.done) {
+			return;
+		}
+
+		yield current.value;
+	}
+}

src/base/_trunc.js

@@ -0,0 +1,42 @@
+import assert from 'assert';
+import deque from '@aureooms/js-collections-deque';
+
+import iter from './iter.js';
+
+/**
+ * Yields all elements of the iterable except the last <code>n</code> ones.
+ *
+ * @example
+ * // returns [ 0 , 1 , 2 ]
+ * list( _trunc( range( 5 ) , 2 ) ) ;
+ *
+ * @param {Iterable} iterable - The input iterable.
+ * @param {Number} n - The nonnegative number of elements to exclude from the output.
+ * @returns {IterableIterator}
+ */
+export default function* _trunc(iterable, n) {
+	assert(Number.isInteger(n) && n >= 0);
+
+	if (n === 0) {
+		yield* iterable;
+		return;
+	}
+
+	const iterator = iter(iterable);
+
+	const buffer = deque(null, n);
+
+	while (n-- > 0) {
+		const event = iterator.next();
+		if (event.done) {
+			return;
+		}
+
+		buffer.append(event.value);
+	}
+
+	for (const value of iterator) {
+		yield buffer.popleft();
+		buffer.append(value);
+	}
+}

src/base/by.js

@@ -1,5 +1,5 @@
-import {iter} from './iter.js';
-import {range} from './range.js';
+import iter from './iter.js';
+import range from './range.js';
 
 /**
  * Yields elements of the input iterable by grouping them into tuples of a
@@ -9,7 +9,7 @@ import {range} from './range.js';
  * @param {Number} n - The size of the yielded tuples.
  * @returns {Iterator}
  */
-export function* by(iterable, n) {
+export default function* by(iterable, n) {
 	const iterator = iter(iterable);
 
 	while (true) {

src/base/consume.js

@@ -5,7 +5,7 @@
  * @param {Number} n - The number of iterations to consume.
  *
  */
-export function consume(iterator, n) {
+export default function consume(iterator, n) {
 	// eslint-disable-next-line no-empty
 	while (n-- > 0 && !iterator.next().done) {}
 }

src/base/count.js

@@ -1,4 +1,4 @@
-import {_count} from './_count.js';
+import _count from './_count.js';
 
 /**
  * Yields increasing or decreasing sequences of numbers. The starting value
@@ -18,6 +18,6 @@ import {_count} from './_count.js';
  * @param {Number} [step=1] - The step between the values.
  * @returns {Iterator}
  */
-export function count(start = 0, step = 1) {
+export default function count(start = 0, step = 1) {
 	return _count(start, step);
 }

src/base/cycle.js

@@ -6,10 +6,10 @@
  * list(head(cycle(range(2)),7)) ;
  *
  * @param {Iterable} iterable - The input iterable.
- * @returns {Iterator}
+ * @returns {IterableIterator}
  *
  */
-export function* cycle(iterable) {
+export default function* cycle(iterable) {
 	const buffer = [];
 
 	for (const item of iterable) {

src/base/drop.js

@@ -1,6 +1,5 @@
-import {iter} from './iter.js';
-import {consume} from './consume.js';
-import {tail} from './tail.js';
+import _drop from './_drop.js';
+import _tail from './_tail.js';
 
 /**
  * Drops the first <code>n</code> values of the input iterable.
@@ -13,15 +12,8 @@ import {tail} from './tail.js';
  *
  * @param {Iterable} iterable - The input iterable.
  * @param {Number} n - The number of values to drop.
- * @returns {Iterator} - The remaining values of the input iterable.
+ * @returns {IterableIterator} - The remaining values of the input iterable.
  */
-export function* drop(iterable, n) {
-	if (n < 0) {
-		yield* tail(iterable, -n);
-		return;
-	}
-
-	const iterator = iter(iterable);
-	consume(iterator, n);
-	yield* iterator;
+export default function drop(iterable, n) {
+	return n < 0 ? _tail(iterable, -n) : _drop(iterable, n);
 }

src/base/exhaust.js

@@ -9,7 +9,7 @@
  * @param {Iterator} iterator - The input iterator.
  *
  */
-export function exhaust(iterator) {
+export default function exhaust(iterator) {
 	// eslint-disable-next-line no-empty,no-unused-vars,prettier/prettier
 	for (const item of iterator) {}
 }

src/base/first.js

@@ -1,7 +1,8 @@
-import {next} from './next.js';
+import next from './next.js';
 
 /**
  * Same as {@link next}.
  * @function first
  */
-export const first = next;
+const first = next;
+export default first;

src/base/frame.js

@@ -1,5 +1,5 @@
-import {iter} from './iter.js';
-import {range} from './range.js';
+import iter from './iter.js';
+import range from './range.js';
 
 /**
  * Yields tuples that contain the current element of the input iterable and the
@@ -15,7 +15,7 @@ import {range} from './range.js';
  * @returns {Iterator}
  *
  */
-export function* frame(iterable, n) {
+export default function* frame(iterable, n) {
 	// Could have an implementation using a deque
 	// that doesn't slice (and thus allocate a new
 	// vector everytime). Though the yield object

src/base/head.js

@@ -1,7 +1,8 @@
-import {take} from './take.js';
+import take from './take.js';
 
 /**
  * Same as {@link take}.
  * @function head
  */
-export const head = take;
+const head = take;
+export default head;

src/base/iter.js

@@ -5,6 +5,6 @@
  * @returns {Iterator}
  *
  */
-export function iter(iterable) {
+export default function iter(iterable) {
 	return iterable[Symbol.iterator]();
 }

src/base/last.js

@@ -1,5 +1,5 @@
-import {next} from './next.js';
-import {tail} from './tail.js';
+import next from './next.js';
+import _tail from './_tail.js';
 
 /**
  * Returns the last value of the input iterable. If the iterable is
@@ -8,6 +8,6 @@ import {tail} from './tail.js';
  * @param {Iterable} iterable - The input iterable.
  * @returns {Object} The last value of the input iterable.
  */
-export function last(iterable) {
-	return next(tail(iterable, 1));
+export default function last(iterable) {
+	return next(_tail(iterable, 1));
 }

src/base/len.js

@@ -9,6 +9,6 @@
  * @returns {Number}
  *
  */
-export function len(array) {
+export default function len(array) {
 	return array.length;
 }

src/base/list.js

@@ -9,6 +9,6 @@
  * @returns {Array}
  *
  */
-export function list(iterable) {
+export default function list(iterable) {
 	return Array.from(iterable);
 }

src/base/ncycle.js

@@ -10,7 +10,7 @@
  * @returns {Iterator}
  *
  */
-export function* ncycle(iterable, n) {
+export default function* ncycle(iterable, n) {
 	const buffer = [];
 
 	for (const item of iterable) {

src/base/next.js

@@ -1,4 +1,4 @@
-import {StopIteration} from './StopIteration.js';
+import StopIteration from './StopIteration.js';
 
 /**
  * Returns the next value of the input iterator. If the iterator is exhausted,
@@ -10,7 +10,7 @@ import {StopIteration} from './StopIteration.js';
  * that the input iterator is exhausted.
  * @returns {Object} The next value of the input iterator.
  */
-export function next(iterator, dflt = undefined) {
+export default function next(iterator, dflt = undefined) {
 	const x = iterator.next();
 
 	if (x.done) {

src/base/pick.js

@@ -8,9 +8,9 @@
  *
  * @param {Object} object - The input object.
  * @param {Iterable} iterable - The input iterable.
- * @returns {Iterator}
+ * @returns {IterableIterator}
  */
-export function* pick(object, iterable) {
+export default function* pick(object, iterable) {
 	for (const key of iterable) {
 		yield object[key];
 	}