From 03a4d8675b47764a847edf765dad10c70d97e765 Mon Sep 17 00:00:00 2001
From: Hunter Wilhelm <71348224+hunterwilhelm@users.noreply.github.com>
Date: Sat, 20 Dec 2025 17:18:17 -0700
Subject: [PATCH] Fixes FIX-230: feature: enable users to pass arrays to
 Decimal.sum

---
 decimal.d.ts        |  1 +
 decimal.global.d.ts |  1 +
 decimal.js          |  3 ++-
 decimal.mjs         |  3 ++-
 doc/API.html        | 15 +++++++++------
 test/modules/sum.js |  8 ++++++++
 6 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/decimal.d.ts b/decimal.d.ts
index 526a896..982a1ee 100644
--- a/decimal.d.ts
+++ b/decimal.d.ts
@@ -270,6 +270,7 @@ export declare class Decimal {
   static sqrt(n: Decimal.Value): Decimal;
   static sub(x: Decimal.Value, y: Decimal.Value): Decimal;
   static sum(...n: Decimal.Value[]): Decimal;
+  static sum(n: Decimal.Value[]): Decimal;
   static tan(n: Decimal.Value): Decimal;
   static tanh(n: Decimal.Value): Decimal;
   static trunc(n: Decimal.Value): Decimal;
diff --git a/decimal.global.d.ts b/decimal.global.d.ts
index a3162a3..7a8f13a 100644
--- a/decimal.global.d.ts
+++ b/decimal.global.d.ts
@@ -291,6 +291,7 @@ export declare class Decimal {
   static sqrt(n: DecimalValue): Decimal;
   static sub(x: DecimalValue, y: DecimalValue): Decimal;
   static sum(...n: Decimal.Value[]): Decimal;
+  static sum(n: Decimal.Value[]): Decimal;
   static tan(n: DecimalValue): Decimal;
   static tanh(n: DecimalValue): Decimal;
   static trunc(n: DecimalValue): Decimal;
diff --git a/decimal.js b/decimal.js
index f7ecafb..b930140 100644
--- a/decimal.js
+++ b/decimal.js
@@ -4856,11 +4856,12 @@
    * Only the result is rounded, not the intermediate calculations.
    *
    * arguments {number|string|bigint|Decimal}
+   * arguments {(number|string|bigint|Decimal)[]}
    *
    */
   function sum() {
     var i = 0,
-      args = arguments,
+      args = arguments.length === 1 && Array.isArray(arguments[0]) ? arguments[0] : arguments,
       x = new this(args[i]);
 
     external = false;
diff --git a/decimal.mjs b/decimal.mjs
index 18dc640..2f93c2f 100644
--- a/decimal.mjs
+++ b/decimal.mjs
@@ -4851,11 +4851,12 @@ function sub(x, y) {
  * Only the result is rounded, not the intermediate calculations.
  *
  * arguments {number|string|bigint|Decimal}
+ * arguments {(number|string|bigint|Decimal)[]}
  *
  */
 function sum() {
   var i = 0,
-    args = arguments,
+    args = arguments.length === 1 && Array.isArray(arguments[0]) ? arguments[0] : arguments,
     x = new this(args[i]);
 
   external = false;
diff --git a/doc/API.html b/doc/API.html
index e11f004..f3ec562 100644
--- a/doc/API.html
+++ b/doc/API.html
@@ -861,22 +861,25 @@ a.equals(b)                    // true</pre>
 
 
 
-    <h5 id="Dsum">sum<code class='inset'>.sum(x [, y, ...]) <i>&rArr; Decimal</i></code></h5>
+    <h5 id="Dsum">sum<code class='inset'>.sum(x [, y, ...]) <i>&rArr; Decimal</i></code><br />
+      <code class='inset'>.sum([x, y, ...]) <i>&rArr; Decimal</i></code></h5>
     <p>
       <code>x</code>: <i>number|string|bigInt|Decimal</i><br />
-      <code>y</code>: <i>number|string|bigInt|Decimal</i>
+      <code>y</code>: <i>number|string|bigInt|Decimal</i><br />
+      <code>[x, y, ...]</code>: <i>Array&lt;number|string|bigInt|Decimal&gt;</i>
     </p>
     <p>
-      Returns a new Decimal whose value is the sum of the <code>arguments</code>,
-      rounded to <a href='#precision'><code>precision</code></a> significant digits using
-      rounding mode <a href='#rounding'><code>rounding</code></a>.<br />
+      Returns a new Decimal whose value is the sum of the arguments (either passed as
+      variadic arguments or as an array), rounded to <a href='#precision'><code>precision</code></a>
+      significant digits using rounding mode <a href='#rounding'><code>rounding</code></a>.<br />
       Only the result is rounded, not the intermediate summations.
     </p>
     <pre>
 x = 5
 y = '16'
 z = new Decimal(-11)
-Decimal.sum(x, y, z)           // '10'</pre>
+Decimal.sum(x, y, z)           // '10'
+Decimal.sum([x, y, z])         // '10'</pre>
 
 
 
diff --git a/test/modules/sum.js b/test/modules/sum.js
index 6dda6f0..9efc1c7 100644
--- a/test/modules/sum.js
+++ b/test/modules/sum.js
@@ -14,6 +14,8 @@ T('sum', function () {
   t(1, 0, '-1');
   t(0, new Decimal('-10'), 0, 0, 0, 0, 0, 10);
   t(11, -11);
+  t([11, -11]);
+  t([0]);
   t(1, '2', new Decimal(3), new Decimal('4'), -10);
   t(new Decimal(-10), '9', new Decimal(0.01), 0.99);
   
@@ -24,6 +26,7 @@ T('sum', function () {
   t(10, 0);
   t(0, 0, 0, 0, 0, 0, 10);
   t(11, -1);
+  t([11, -1]);
   t(1, '2', new Decimal(3), new Decimal('4'));
   t('9', new Decimal(0.01), 0.99);
 
@@ -61,4 +64,9 @@ T('sum', function () {
   t(0, new Decimal('-Infinity'), '9', new Decimal(0), 11);
   t(0, '9', new Decimal(0), 11, -Infinity);
   t(4, new Decimal(-Infinity), 0, '9', new Decimal(0), -Infinity, 2);
+  t([4, new Decimal(-Infinity), 0, '9', new Decimal(0), -Infinity, 2]);
+
+  expected = new Decimal(100e3);
+
+  t(Array.from({ length: 100e3 }).fill(1));
 });
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