[#94] Backend

https://project.mdnd-it.cc/work_packages/94

SerpentRace_Backend/node_modules/stream-json/utils/Utf8Stream.js

@@ -0,0 +1,53 @@
+'use strict';
+
+const {Transform} = require('stream');
+const {StringDecoder} = require('string_decoder');
+
+class Utf8Stream extends Transform {
+  constructor(options) {
+    super(Object.assign({}, options, {writableObjectMode: false}));
+    this._buffer = '';
+  }
+
+  _transform(chunk, encoding, callback) {
+    if (typeof chunk == 'string') {
+      this._transform = this._transformString;
+    } else {
+      this._stringDecoder = new StringDecoder();
+      this._transform = this._transformBuffer;
+    }
+    this._transform(chunk, encoding, callback);
+  }
+
+  _transformBuffer(chunk, _, callback) {
+    this._buffer += this._stringDecoder.write(chunk);
+    this._processBuffer(callback);
+  }
+
+  _transformString(chunk, _, callback) {
+    this._buffer += chunk.toString();
+    this._processBuffer(callback);
+  }
+
+  _processBuffer(callback) {
+    if (this._buffer) {
+      this.push(this._buffer, 'utf8');
+      this._buffer = '';
+    }
+    callback(null);
+  }
+
+  _flushInput() {
+    // meant to be called from _flush()
+    if (this._stringDecoder) {
+      this._buffer += this._stringDecoder.end();
+    }
+  }
+
+  _flush(callback) {
+    this._flushInput();
+    this._processBuffer(callback);
+  }
+}
+
+module.exports = Utf8Stream;