From f4d0c50a8b4480b013b99faafb4a2a69f1bd689f Mon Sep 17 00:00:00 2001
From: Angus MacDonald <amacdonald@google.com>
Date: Fri, 27 Nov 2020 14:00:41 -0600
Subject: [PATCH] Add arrayf.min function

---
 src/arrayf/arrayf.ts | 41 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/src/arrayf/arrayf.ts b/src/arrayf/arrayf.ts
index c53ee4696a..9b6b9749f8 100644
--- a/src/arrayf/arrayf.ts
+++ b/src/arrayf/arrayf.ts
@@ -28,5 +28,44 @@ export class arrayf {
         return output;
     }
 
+    /**
+     * Given a set of values and score functions returns the value with the
+     * lowest score. If two objects tie using the first score function then the
+     * next given score function (if any) is used to break the tie.
+     * ```
+     * const values = [2.2, 2.1, 3.4];
+     * const fnA = (x) => Math.floor(x);
+     * const fnB = (x) => x;
+     * arrayf.min(values, fnA); // Returns 2.2
+     * arrayf.min(values, fnA, fnB); // Returns 2.1
+     * ```
+     */
+    static min<T>(values: T[], ...scoreFns: Array<(v: T) => number>): T {
+        let minValue: T;
+        let minScore: number = Number.POSITIVE_INFINITY;
+
+        const scoreFn = scoreFns[0];
 
-}
\ No newline at end of file
+        values.forEach((value) => {
+            const score = scoreFn(value);
+            if (minScore > score) {
+                minValue = value;
+                minScore = score;
+            } else if (minScore === score && scoreFns.length > 1) {
+                let i = 1;
+                let tieBreaker = scoreFns[i];
+                while (
+                    i < scoreFns.length &&
+                    tieBreaker(minValue) === tieBreaker(value)
+                ) {
+                    tieBreaker = scoreFns[i++];
+                }
+
+                if (tieBreaker(minValue) > tieBreaker(value)) {
+                    minValue = value;
+                }
+            }
+        });
+        return minValue;
+    }
+}