From c6157e62e900e2ecb63800048c1106f231b49760 Mon Sep 17 00:00:00 2001
From: Andrew Heard <andrewheard@google.com>
Date: Wed, 28 Feb 2024 12:41:08 -0500
Subject: [PATCH] Add comment about converting to `Decimal` before encode

---
 Sources/GoogleAI/JSONValue.swift | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Sources/GoogleAI/JSONValue.swift b/Sources/GoogleAI/JSONValue.swift
index a279e91..5ce52cd 100644
--- a/Sources/GoogleAI/JSONValue.swift
+++ b/Sources/GoogleAI/JSONValue.swift
@@ -75,6 +75,11 @@ extension JSONValue: Encodable {
     case .null:
       try container.encodeNil()
     case let .number(numberValue):
+      // Convert to `Decimal` before encoding for consistent floating-point serialization across
+      // platforms. E.g., `Double` serializes 3.14159 as 3.1415899999999999 in some cases and
+      // 3.14159 in others. See
+      // https://forums.swift.org/t/jsonencoder-encodable-floating-point-rounding-error/41390/4 for
+      // more details.
       try container.encode(Decimal(numberValue))
     case let .string(stringValue):
       try container.encode(stringValue)