From 23fcb9862aeb866d6c13b46bcf7155bec97b5c0d Mon Sep 17 00:00:00 2001
From: Jos de Jong <wjosdejong@gmail.com>
Date: Wed, 15 Nov 2023 13:51:12 +0100
Subject: [PATCH] fix #2761: extend function `round` with support for units

---
 test/node-tests/doc.test.js        |  2 +-
 test/typescript-tests/testTypes.ts | 13 +++++++++++
 types/index.d.ts                   | 36 +++++++++++++++++++++---------
 3 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/test/node-tests/doc.test.js b/test/node-tests/doc.test.js
index a33b2f7c5e..e01b18a3ef 100644
--- a/test/node-tests/doc.test.js
+++ b/test/node-tests/doc.test.js
@@ -99,7 +99,7 @@ const knownProblems = new Set([
   'mod', 'invmod', 'floor', 'fix', 'expm1', 'exp', 'dotPow', 'dotMultiply',
   'dotDivide', 'divide', 'ceil', 'cbrt', 'add', 'usolveAll', 'usolve', 'slu',
   'rationalize', 'qr', 'lusolve', 'lup', 'lsolveAll', 'lsolve', 'derivative',
-  'symbolicEqual', 'map', 'schur', 'sylvester', 'freqz'
+  'symbolicEqual', 'map', 'schur', 'sylvester', 'freqz', 'round'
 ])
 
 function maybeCheckExpectation (name, expected, expectedFrom, got, gotFrom) {
diff --git a/test/typescript-tests/testTypes.ts b/test/typescript-tests/testTypes.ts
index 8ce11c3f87..730fb665f7 100644
--- a/test/typescript-tests/testTypes.ts
+++ b/test/typescript-tests/testTypes.ts
@@ -633,6 +633,9 @@ Chaining examples
   expectTypeOf(math.chain([1]).round()).toMatchTypeOf<
     MathJsChain<MathCollection>
   >()
+  expectTypeOf(
+    math.chain(math.unit('5.2cm')).round(math.unit('cm'))
+  ).toMatchTypeOf<MathJsChain<Unit>>()
 
   // cube
   expectTypeOf(math.chain(1).cube()).toMatchTypeOf<MathJsChain<number>>()
@@ -1904,6 +1907,16 @@ Function round examples
     math.complex(3.2, -2.7)
   )
 
+  // unit input
+  assert.deepStrictEqual(
+    math.round(math.unit('5.21 cm'), math.unit('cm')),
+    math.unit('5 cm')
+  )
+  assert.deepStrictEqual(
+    math.round(math.unit('5.21 cm'), 1, math.unit('cm')),
+    math.unit('5.2 cm')
+  )
+
   // array input
   assert.deepStrictEqual(math.round([3.2, 3.8, -4.7]), [3, 4, -5])
   assert.deepStrictEqual(math.round([3.21, 3.82, -4.71], 1), [3.2, 3.8, -4.7])
diff --git a/types/index.d.ts b/types/index.d.ts
index 22e467b0ff..7ebc8e0f79 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -1103,7 +1103,7 @@ export interface MathJsInstance extends MathJsFactory {
     x: T,
     n?: number | BigNumber
   ): NoLiteralType<T>
-  round<U extends MathCollection>(x: MathNumericType | U, n: U): U
+  round<U extends MathCollection>(x: MathNumericType, n: U): U
   round(x: Unit, n: number | BigNumber, unit: Unit): Unit
   round(x: Unit, unit: Unit): Unit
   round<U extends MathCollection>(x: U, unit: Unit): U
@@ -4745,27 +4745,41 @@ export interface MathJsChain<TValue> {
    */
   round<T extends MathNumericType | MathCollection>(
     this: MathJsChain<T>,
-    n?: number | BigNumber
-  ): NoLiteralType<T>
+    n?: number | BigNumber | MathCollection
+  ): MathJsChain<T>
   round<U extends MathCollection>(
     this: MathJsChain<MathNumericType | U>,
     n: U
-  ): U
-  round(this: MathJsChain<Unit>, n: number | BigNumber, unit: Unit): Unit
-  round(this: MathJsChain<Unit>, unit: Unit): Unit
-  round<U extends MathCollection>(this: MathJsChain<U>, unit: Unit): U
+  ): MathJsChain<U>
+  round(
+    this: MathJsChain<Unit>,
+    n: number | BigNumber,
+    unit: Unit
+  ): MathJsChain<Unit>
+  round(this: MathJsChain<Unit>, unit: Unit): MathJsChain<Unit>
+  round<U extends MathCollection>(
+    this: MathJsChain<U>,
+    unit: Unit
+  ): MathJsChain<U>
   round<U extends MathCollection>(
     this: MathJsChain<U>,
     n: number | BigNumber,
     unit: Unit
-  ): U
-  round<U extends MathCollection>(this: MathJsChain<Unit>, n: U, unit: Unit): U
+  ): MathJsChain<U>
+  round<U extends MathCollection>(
+    this: MathJsChain<Unit>,
+    n: U,
+    unit: Unit
+  ): MathJsChain<U>
   round<U extends MathCollection>(
     this: MathJsChain<Unit>,
     n: number | BigNumber,
     unit: U
-  ): U
-  round<U extends MathCollection>(this: MathJsChain<Unit>, unit: U): U
+  ): MathJsChain<U>
+  round<U extends MathCollection>(
+    this: MathJsChain<Unit>,
+    unit: U
+  ): MathJsChain<U>
 
   // End of rounding group