Shared helper function for bn/bi min/max compares (#1527)

* Shared helper function for bn/bi min/max compares

* min/max test

packages/util/src/bi/helpers.ts

@@ -0,0 +1,21 @@
+// Copyright 2017-2022 @polkadot/util authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import { assert } from '../assert';
+
+/** @internal */
+export function createCmp <T> (cmp: (a: T, b: T) => boolean): (...items: T[]) => T {
+  return (...items: T[]): T => {
+    assert(items.length >= 1, 'Must provide one or more arguments');
+
+    let result = items[0];
+
+    for (let i = 1; i < items.length; i++) {
+      if (cmp(items[i], result)) {
+        result = items[i];
+      }
+    }
+
+    return result;
+  };
+}

packages/util/src/bi/max.spec.ts

@@ -25,6 +25,6 @@ describe('nMax', (): void => {
   it('fails when no items are available', (): void => {
     expect(
       () => nMax()
-    ).toThrow(/Must provide one or more bigint arguments/);
+    ).toThrow(/Must provide one or more arguments/);
   });
 });

packages/util/src/bi/min.spec.ts

@@ -19,6 +19,6 @@ describe('nMin', (): void => {
   it('fails when no items are available', (): void => {
     expect(
       () => nMin()
-    ).toThrow(/Must provide one or more bigint arguments/);
+    ).toThrow(/Must provide one or more arguments/);
   });
 });

packages/util/src/bi/min.ts

@@ -1,7 +1,7 @@
 // Copyright 2017-2022 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { assert } from '../assert';
+import { createCmp } from './helpers';
 
 /** @internal */
 function gt (a: bigint, b: bigint): boolean {
@@ -13,23 +13,6 @@ function lt (a: bigint, b: bigint): boolean {
   return a < b;
 }
 
-/** @internal */
-function createCmp (cmp: (a: bigint, b: bigint) => boolean): (...items: bigint[]) => bigint {
-  return (...items: bigint[]): bigint => {
-    assert(items.length >= 1, 'Must provide one or more bigint arguments');
-
-    let result = items[0];
-
-    for (let i = 1; i < items.length; i++) {
-      if (cmp(items[i], result)) {
-        result = items[i];
-      }
-    }
-
-    return result;
-  };
-}
-
 /**
  * @name nMax
  * @summary Finds and returns the highest value in an array of bigint.

packages/util/src/bn/max.spec.ts

@@ -25,6 +25,6 @@ describe('bnMax', (): void => {
   it('fails when no items are available', (): void => {
     expect(
       () => bnMax()
-    ).toThrow(/Must provide one or more BN arguments/);
+    ).toThrow(/Must provide one or more arguments/);
   });
 });

packages/util/src/bn/min.spec.ts

@@ -15,4 +15,10 @@ describe('bnMin', (): void => {
       bnMin(new BN(1))
     ).toEqual(new BN(1));
   });
+
+  it('fails when no items are available', (): void => {
+    expect(
+      () => bnMin()
+    ).toThrow(/Must provide one or more arguments/);
+  });
 });

packages/util/src/bn/min.ts

@@ -1,22 +1,17 @@
 // Copyright 2017-2022 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { assert } from '../assert';
+import { createCmp } from '../bi/helpers';
 import { BN } from './bn';
 
 /** @internal */
-function createCmp (cmp: (a: BN, b: BN) => BN): (...items: BN[]) => BN {
-  return (...items: BN[]): BN => {
-    assert(items.length >= 1, 'Must provide one or more BN arguments');
+function gt (a: BN, b: BN): boolean {
+  return a.gt(b);
+}
 
-    let result = items[0];
-
-    for (let i = 1; i < items.length; i++) {
-      result = cmp(result, items[i]);
-    }
-
-    return result;
-  };
+/** @internal */
+function lt (a: BN, b: BN): boolean {
+  return a.lt(b);
 }
 
 /**
@@ -32,7 +27,7 @@ function createCmp (cmp: (a: BN, b: BN) => BN): (...items: BN[]) => BN {
  * bnMax([new BN(1), new BN(3), new BN(2)]).toString(); // => '3'
  * ```
  */
-export const bnMax = createCmp(BN.max);
+export const bnMax = createCmp(gt);
 
 /**
  * @name bnMin
@@ -47,4 +42,4 @@ export const bnMax = createCmp(BN.max);
  * bnMin([new BN(1), new BN(3), new BN(2)]).toString(); // => '1'
  * ```
  */
-export const bnMin = createCmp(BN.min);
+export const bnMin = createCmp(lt);