typings: add typing for string_decoder

PR-URL: #61368
Reviewed-By: Aviv Keller <[email protected]>
Reviewed-By: Benjamin Gruenbaum <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Daijiro Wachi <[email protected]>

Author: kimtaejin3

typings/globals.d.ts

@@ -18,6 +18,7 @@ import { OSBinding } from './internalBinding/os';
 import { ProcessBinding } from './internalBinding/process';
 import { SeaBinding } from './internalBinding/sea';
 import { SerdesBinding } from './internalBinding/serdes';
+import { StringDecoderBinding } from './internalBinding/string_decoder';
 import { SymbolsBinding } from './internalBinding/symbols';
 import { TimersBinding } from './internalBinding/timers';
 import { TypesBinding } from './internalBinding/types';
@@ -52,6 +53,7 @@ interface InternalBindingMap {
   process: ProcessBinding;
   sea: SeaBinding;
   serdes: SerdesBinding;
+  string_decoder: StringDecoderBinding;
   symbols: SymbolsBinding;
   timers: TimersBinding;
   types: TypesBinding;

typings/internalBinding/string_decoder.d.ts

@@ -0,0 +1,19 @@
+declare namespace InternalStringDecoderBinding {
+  type Buffer = Uint8Array;
+}
+
+export interface StringDecoderBinding {
+  readonly kIncompleteCharactersStart: number;
+  readonly kIncompleteCharactersEnd: number;
+  readonly kMissingBytes: number;
+  readonly kBufferedBytes: number;
+  readonly kEncodingField: number;
+  readonly kNumFields: number;
+  readonly kSize: number;
+
+  readonly encodings: string[];
+
+  decode(decoder: InternalStringDecoderBinding.Buffer, buffer: ArrayBufferView): string;
+  flush(decoder: InternalStringDecoderBinding.Buffer): string;
+}
+