@@ -937,7 +937,11 @@ class Zstd extends ZlibBase {
       if (isAnyArrayBuffer(dictionary)) {
         dictionary = new Uint8Array(dictionary);
       } else {
-        dictionary = undefined;
+        throw new ERR_INVALID_ARG_TYPE(
+          'options.dictionary',
+          ['Buffer', 'TypedArray', 'DataView', 'ArrayBuffer'],
+          dictionary,
+        );
       }
     }
 
 
@@ -1820,8 +1820,7 @@ CompressionError ZstdDecompressContext::Init(uint64_t pledged_src_size,
 }
 
 CompressionError ZstdDecompressContext::ResetStream() {
-  const size_t result =
-      ZSTD_DCtx_reset(dctx_.get(), ZSTD_reset_session_only);
+  const size_t result = ZSTD_DCtx_reset(dctx_.get(), ZSTD_reset_session_only);
   if (ZSTD_isError(result)) {
     const ZSTD_ErrorCode error = ZSTD_getErrorCode(result);
     return CompressionError(
 
@@ -40,3 +40,24 @@ for (const dict of [arrayBuffer, uint8, dataView]) {
   const decompressed = zlib.zstdDecompressSync(compressed, { dictionary: dict });
   assert.strictEqual(decompressed.toString(), input.toString());
 }
+
+for (const dictionary of [null, 'string', 123, true, {}, [1, 2, 3]]) {
+  const options = { dictionary };
+  const expected = {
+    code: 'ERR_INVALID_ARG_TYPE',
+    name: 'TypeError',
+  };
+
+  assert.throws(() => zlib.createZstdCompress(options), expected);
+  assert.throws(() => zlib.createZstdDecompress(options), expected);
+  assert.throws(() => zlib.zstdCompressSync(input, options), expected);
+  assert.throws(() => zlib.zstdDecompressSync(input, options), expected);
+  assert.throws(
+    () => zlib.zstdCompress(input, options, common.mustNotCall()),
+    expected,
+  );
+  assert.throws(
+    () => zlib.zstdDecompress(input, options, common.mustNotCall()),
+    expected,
+  );
+}
Original file line number	Diff line number	Diff line change
`@@ -937,7 +937,11 @@ class Zstd extends ZlibBase {`
`937`	`937`	`if (isAnyArrayBuffer(dictionary)) {`
`938`	`938`	`dictionary = new Uint8Array(dictionary);`
`939`	`939`	`} else {`
`940`		`- dictionary = undefined;`
	`940`	`+ throw new ERR_INVALID_ARG_TYPE(`
	`941`	`+ 'options.dictionary',`
	`942`	`+ ['Buffer', 'TypedArray', 'DataView', 'ArrayBuffer'],`
	`943`	`+ dictionary,`
	`944`	`+ );`
`941`	`945`	`}`
`942`	`946`	`}`
`943`	`947`
Original file line number	Diff line number	Diff line change
`@@ -1820,8 +1820,7 @@ CompressionError ZstdDecompressContext::Init(uint64_t pledged_src_size,`
`1820`	`1820`	`}`
`1821`	`1821`
`1822`	`1822`	`CompressionError ZstdDecompressContext::ResetStream() {`
`1823`		`- const size_t result =`
`1824`		`- ZSTD_DCtx_reset(dctx_.get(), ZSTD_reset_session_only);`
	`1823`	`+ const size_t result = ZSTD_DCtx_reset(dctx_.get(), ZSTD_reset_session_only);`
`1825`	`1824`	`if (ZSTD_isError(result)) {`
`1826`	`1825`	`const ZSTD_ErrorCode error = ZSTD_getErrorCode(result);`
`1827`	`1826`	`return CompressionError(`