From 706c2bfd41088fdca783f2fc1f152453f91fc784 Mon Sep 17 00:00:00 2001
From: gregdyke <gregdyke@gmail.com>
Date: Tue, 31 May 2022 17:22:34 +0100
Subject: [PATCH] fix: provide initial values to reduce functions in generated
 js (#6178)

---
 generators/javascript/math.js        | 4 ++--
 tests/generators/golden/generated.js | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/generators/javascript/math.js b/generators/javascript/math.js
index 0e90615e5..39d768843 100644
--- a/generators/javascript/math.js
+++ b/generators/javascript/math.js
@@ -222,7 +222,7 @@ JavaScript['math_on_list'] = function(block) {
     case 'SUM':
       list = JavaScript.valueToCode(block, 'LIST',
           JavaScript.ORDER_MEMBER) || '[]';
-      code = list + '.reduce(function(x, y) {return x + y;})';
+      code = list + '.reduce(function(x, y) {return x + y;}, 0)';
       break;
     case 'MIN':
       list = JavaScript.valueToCode(block, 'LIST',
@@ -238,7 +238,7 @@ JavaScript['math_on_list'] = function(block) {
       // mathMean([null,null,1,3]) === 2.0.
       const functionName = JavaScript.provideFunction_('mathMean', `
 function ${JavaScript.FUNCTION_NAME_PLACEHOLDER_}(myList) {
-  return myList.reduce(function(x, y) {return x + y;}) / myList.length;
+  return myList.reduce(function(x, y) {return x + y;}, 0) / myList.length;
 }
 `);
       list = JavaScript.valueToCode(block, 'LIST',
diff --git a/tests/generators/golden/generated.js b/tests/generators/golden/generated.js
index 48a4e20ac..2778376c2 100644
--- a/tests/generators/golden/generated.js
+++ b/tests/generators/golden/generated.js
@@ -476,7 +476,7 @@ function test_change() {
 }
 
 function mathMean(myList) {
-  return myList.reduce(function(x, y) {return x + y;}) / myList.length;
+  return myList.reduce(function(x, y) {return x + y;}, 0) / myList.length;
 }
 
 function mathMedian(myList) {
@@ -538,7 +538,7 @@ function mathRandomList(list) {
 
 // Tests the "list operation" blocks.
 function test_operations_on_list() {
-  assertEquals([3, 4, 5].reduce(function(x, y) {return x + y;}), 12, 'sum');
+  assertEquals([3, 4, 5].reduce(function(x, y) {return x + y;}, 0), 12, 'sum');
   assertEquals(Math.min.apply(null, [3, 4, 5]), 3, 'min');
   assertEquals(Math.max.apply(null, [3, 4, 5]), 5, 'max');
   assertEquals(mathMean([3, 4, 5]), 4, 'average');