fix: preserve decimal digits when truncating counts

HISTORY.md

@@ -1,3 +1,7 @@
+# Unreleased
+
+- fix: preserve decimal digits when truncating with `maxDecimalPoints`
+
 # 3.35.0 / 2026-09-10
 
 - new: Azerbaijani support (`az`)

README.md

@@ -455,6 +455,7 @@ Lovingly made by [Evan Hahn](https://evanhahn.com/) with help from:
 - [Kristijan Jesenski](https://github.com/kjesenski) for Slovenian support
 - [Michal Karzel](https://github.com/Misioka) for improving Arabic support
 - [Mikias Menjeta](https://github.com/OMikiasO) for Amharic support
+- [Huanyi Xie](https://github.com/xiehuanyi) for fixing decimal truncation
 
 Licensed under the permissive [Unlicense](https://unlicense.org/). Enjoy!
 

bower.json

@@ -34,7 +34,8 @@
     "Michal Karzel (https://github.com/Misioka)",
     "Batmend Ganbaatar (https://github.com/theironbatka)",
     "Mikias Menjeta (https://github.com/OMikiasO)",
-    "Marko Plaznik (https://github.com/ohicee)"
+    "Marko Plaznik (https://github.com/ohicee)",
+    "Huanyi Xie (https://github.com/xiehuanyi)"
   ],
   "version": "3.35.0",
   "description": "Convert millisecond durations to English and many other languages.",

humanize-duration.js

@@ -1330,6 +1330,23 @@
       throw new Error("No language found.");
     }
 
+    /**
+     * @internal
+     * @param {number} count
+     * @param {number} decimalPoints
+     * @returns {number}
+     */
+    function truncateCount(count, decimalPoints) {
+      var parts = count.toString().split("e");
+      var shifted = Number(
+        parts[0] + "e" + ((Number(parts[1]) || 0) + decimalPoints)
+      );
+      if (!isFinite(shifted)) return count;
+
+      parts = Math.floor(shifted).toString().split("e");
+      return Number(parts[0] + "e" + ((Number(parts[1]) || 0) - decimalPoints));
+    }
+
     /**
      * @internal
      * @param {Piece} piece
@@ -1366,8 +1383,7 @@
       var normalizedUnitCount =
         maxDecimalPoints === void 0
           ? unitCount
-          : Math.floor(unitCount * Math.pow(10, maxDecimalPoints)) /
-            Math.pow(10, maxDecimalPoints);
+          : truncateCount(unitCount, maxDecimalPoints);
       var countStr = normalizedUnitCount.toString();
 
       if (language._hideCountIf2 && normalizedUnitCount === 2) {

package.json

@@ -34,7 +34,8 @@
     "Michal Karzel (https://github.com/Misioka)",
     "Batmend Ganbaatar (https://github.com/theironbatka)",
     "Mikias Menjeta (https://github.com/OMikiasO)",
-    "Marko Plaznik (https://github.com/ohicee)"
+    "Marko Plaznik (https://github.com/ohicee)",
+    "Huanyi Xie (https://github.com/xiehuanyi)"
   ],
   "version": "3.35.0",
   "description": "Convert millisecond durations to English and many other languages.",

test/humanizer.js

@@ -162,6 +162,20 @@ describe("humanizer", function () {
     assert.strictEqual(h(7999), "7.999 seconds");
   });
 
+  it('preserves decimal digits when truncating with "maxDecimalPoints"', function () {
+    const h = humanizer({ units: ["s"], maxDecimalPoints: 2 });
+
+    assert.strictEqual(h(1150), "1.15 seconds");
+    assert.strictEqual(h(2300), "2.3 seconds");
+    assert.strictEqual(h(1159), "1.15 seconds");
+    assert.strictEqual(
+      h(0.00115, { maxDecimalPoints: 8 }),
+      "0.00000115 seconds"
+    );
+    assert.strictEqual(h(1150, { maxDecimalPoints: 309 }), "1.15 seconds");
+    assert.strictEqual(h(1.15e24), "1.15e+21 seconds");
+  });
+
   it('pluralizes based on the count rendered by "maxDecimalPoints"', function () {
     const h = humanizer({ maxDecimalPoints: 0 });