From 2239569358cfdcd58ef03892c40777a49229052a Mon Sep 17 00:00:00 2001
From: Damien Cassou <damien@cassou.me>
Date: Thu, 7 May 2020 16:04:31 +0200
Subject: [PATCH] Fix totalLength interpretation with negative numbers for #425

---
 CHANGELOG.md                  | 1 +
 src/formatting.js             | 8 +++++++-
 tests/src/formatting-tests.js | 2 ++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 072ece44..a68e6d1f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 - Bump `lodash.template` to 4.5.0
 - Fix #359: Add Bytes I18N possibility + French translation
 - Fix #474: Fix Bytes formatting tests and coverage
+- Fix #425: Fix interpretation of totalLength with negative numbers. Thanks @DamienCassou
 
 ### 2.2.0
 
diff --git a/src/formatting.js b/src/formatting.js
index e0db816a..96950389 100644
--- a/src/formatting.js
+++ b/src/formatting.js
@@ -371,8 +371,14 @@ function computeAverage({value, forceAverage, abbreviations, spaceSeparated = fa
     }
 
     if (totalLength) {
+        let isNegative = value < 0;
         let characteristic = value.toString().split(".")[0];
-        mantissaPrecision = Math.max(totalLength - characteristic.length, 0);
+
+        let characteristicLength = isNegative
+            ? characteristic.length - 1
+            : characteristic.length;
+
+        mantissaPrecision = Math.max(totalLength - characteristicLength, 0);
     }
 
     return {value, abbreviation, mantissaPrecision};
diff --git a/tests/src/formatting-tests.js b/tests/src/formatting-tests.js
index 9c62030d..94812654 100644
--- a/tests/src/formatting-tests.js
+++ b/tests/src/formatting-tests.js
@@ -2711,6 +2711,8 @@ describe("formatting", () => {
                     // [18823578.85, "6 a", "18823.6 k"],
                     // [188235773.85, "6 a", "188236 k"],
 
+                    [-1.2345, ",4 a", "-1.234"],
+
                     // large numbers
                     [100, "0,0[.]0000", "100"],
                     [1e23, "0,0[.]0000", "100,000,000,000,000,000,000,000"],