feat(arrays): add binarySearchNumeric()

packages/arrays/src/binary-search.ts

@@ -1,10 +1,10 @@
 import { Comparator, Fn } from "@thi.ng/api";
-import { compare } from "@thi.ng/compare";
+import { compare, compareNumAsc } from "@thi.ng/compare";
 
 /**
  * Returns the supposed index of `x` in pre-sorted array-like collection
  * `buf`. If `x` can't be found, returns `-index-1`, representing the
- * negative of the index were `x` to be inserted into `buf`. E.g if the
+ * negative of the index, were `x` to be inserted into `buf`. E.g if the
  * return value is -3, `x` would appear/insert at index 2.
  *
  * ```
@@ -46,3 +46,33 @@ export const binarySearch = <A, B>(
     }
     return -low - 1;
 };
+
+/**
+ * Similar to `binarySearch()`, but optimized for numeric arrays and
+ * supporting custom comparators (default: `compareNumAsc` from
+ * thi.ng/compare pkg).
+ *
+ * @param buf
+ * @param x
+ * @param cmp
+ */
+export const binarySearchNumeric = (
+    buf: ArrayLike<number>,
+    x: number,
+    cmp: Comparator<number> = compareNumAsc
+) => {
+    let low = 0;
+    let high = buf.length - 1;
+    while (low <= high) {
+        const mid = (low + high) >>> 1;
+        const c = cmp(buf[mid], x);
+        if (c < 0) {
+            low = mid + 1;
+        } else if (c > 0) {
+            high = mid - 1;
+        } else {
+            return mid;
+        }
+    }
+    return -low - 1;
+};