Add polyfill for isSafeInteger

build-config.js

@@ -147,6 +147,14 @@ const babelTsWithPresetEnvTargets = ({ targets, stripConsole }) =>
                 'isFiniteNumber',
                 path.resolve('src/polyfills/number'),
               );
+            } else if (
+              espath.get('callee').matchesPattern('Number.isSafeInteger')
+            ) {
+              espath.node.callee = importHelper.addNamed(
+                espath,
+                'isSafeInteger',
+                path.resolve('src/polyfills/number'),
+              );
             } else if (
               espath.get('callee').matchesPattern('Number.MAX_SAFE_INTEGER')
             ) {

src/polyfills/number.ts

@@ -1,7 +1,15 @@
+// https://caniuse.com/mdn-javascript_builtins_number_isfinite
 export const isFiniteNumber =
   Number.isFinite ||
   function (value) {
     return typeof value === 'number' && isFinite(value);
   };
 
+// https://caniuse.com/mdn-javascript_builtins_number_issafeinteger
+export const isSafeInteger =
+  Number.isSafeInteger ||
+  function (value) {
+    return typeof value === 'number' && Math.abs(value) <= MAX_SAFE_INTEGER;
+  };
+
 export const MAX_SAFE_INTEGER = Number.MAX_SAFE_INTEGER || 9007199254740991;

src/utils/mp4-tools.ts

@@ -548,7 +548,7 @@ export function getStartDTS(
             // convert base time to seconds
             const startTime = baseTime / scale;
             if (
-              isFinite(startTime) &&
+              Number.isFinite(startTime) &&
               (result === null || startTime < result)
             ) {
               return startTime;
@@ -560,7 +560,7 @@ export function getStartDTS(
       );
       if (
         start !== null &&
-        isFinite(start) &&
+        Number.isFinite(start) &&
         (result === null || start < result)
       ) {
         return start;