lib: handle Float16Array in node:v8 serdes

lib/v8.js

@@ -289,6 +289,7 @@ function arrayBufferViewTypeToIndex(abView) {
   // Index 10 is FastBuffer.
   if (type === '[object BigInt64Array]') return 11;
   if (type === '[object BigUint64Array]') return 12;
+  if (type === '[object Float16Array]') return 13;
   return -1;
 }
 
@@ -306,6 +307,9 @@ function arrayBufferViewIndexToType(index) {
   if (index === 10) return FastBuffer;
   if (index === 11) return BigInt64Array;
   if (index === 12) return BigUint64Array;
+  // TODO(bartlomieju): use a primordial, once `Float16Array` is available in stable V8
+  // eslint-disable-line no-undef
+  if (index === 13) return Float16Array;
   return undefined;
 }
 

test/parallel/test-v8-serdes.js

@@ -1,4 +1,4 @@
-// Flags: --expose-internals
+// Flags: --expose-internals --js-float16array
 
 'use strict';
 
@@ -26,6 +26,9 @@
   Buffer.from([1, 2, 3, 4]),
   new BigInt64Array([42n]),
   new BigUint64Array([42n]),
+  // TODO(bartlomieju): once `Float16Array` is available in stable V8, remove the lint below and `--js-float16array` flag up top
+  // eslint-disable-line no-undef
+  new Float16Array([1, 2, 3, 4]),
   undefined,
   null,
   42,