✨ feat(randrange): Export kernel constructor _randrange.

Author: make-github-pseudonymous-again

src/api/randrange.js

@@ -1,3 +1,4 @@
+import _randrange from '../kernel/_randrange.js';
 import randint from './randint.js';
 
 /**
@@ -13,20 +14,11 @@ import randint from './randint.js';
  *
  * TODO: Handle empty ranges.
  *
+ * @function
  * @param {number} [start=0] - The starting value.
  * @param {number} stop - The stopping value.
  * @param {number} [step=1] - The step value.
  * @return {number} The picked element.
  */
-const randrange = (start, stop, step) => {
-	if (stop === undefined) return randint(0, start);
-	if (step === undefined) step = 1;
-
-	if (stop >= start) {
-		return start + step * randint(0, Math.floor((stop - start) / step));
-	}
-
-	return start + step * randint(0, Math.floor((start - stop) / -step));
-};
-
+const randrange = _randrange(randint);
 export default randrange;

src/index.js

@@ -12,5 +12,6 @@ export {default as _fisheryates} from './kernel/_fisheryates.js';
 export {default as _fisheryates_inside_out} from './kernel/_fisheryates_inside_out.js';
 export {default as _randfloat} from './kernel/_randfloat.js';
 export {default as _randint} from './kernel/_randint.js';
+export {default as _randrange} from './kernel/_randrange.js';
 export {default as _shuffle} from './kernel/_shuffle.js';
 export {default as _waterman} from './kernel/_waterman.js';

src/kernel/_randrange.js

@@ -0,0 +1,40 @@
+/**
+ * Builds a randrange function given a randint function.
+ *
+ * @param {Function} randint The randint function.
+ * @return {Function} The choice function.
+ */
+const _randrange = (randint) => {
+	/**
+	 * Pick an element from range(start, stop, step) uniformly at random.
+	 *
+	 * Return an element from range(start, stop, step) selected uniformly at random.
+	 * If step is positive, this set corresponds to
+	 * {x: x in [start, stop[ AND x % step = 0}.
+	 * If step is negative, the range has to be given in reverse order, that is,
+	 * largest value first, smallest value second. Both the starting value and the
+	 * step value are optional. By default the starting value is <code>0</code>.
+	 * The default for the step value is <code>1</code>.
+	 *
+	 * TODO: Handle empty ranges.
+	 *
+	 * @param {number} [start=0] - The starting value.
+	 * @param {number} stop - The stopping value.
+	 * @param {number} [step=1] - The step value.
+	 * @return {number} The picked element.
+	 */
+	const randrange = (start, stop, step) => {
+		if (stop === undefined) return randint(0, start);
+		if (step === undefined) step = 1;
+
+		if (stop >= start) {
+			return start + step * randint(0, Math.floor((stop - start) / step));
+		}
+
+		return start + step * randint(0, Math.floor((start - stop) / -step));
+	};
+
+	return randrange;
+};
+
+export default _randrange;