[#94] Backend

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

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

@@ -0,0 +1,44 @@
+'use strict';
+
+const {Transform} = require('stream');
+const withParser = require('./withParser');
+
+class Batch extends Transform {
+  static make(options) {
+    return new Batch(options);
+  }
+
+  static withParser(options) {
+    return withParser(Batch.make, options);
+  }
+
+  constructor(options) {
+    super(Object.assign({}, options, {writableObjectMode: true, readableObjectMode: true}));
+    this._batchSize = 1000;
+    if (options && typeof options.batchSize == 'number' && options.batchSize > 0) {
+      this._batchSize = options.batchSize;
+    }
+    this._accumulator = [];
+  }
+
+  _transform(chunk, _, callback) {
+    this._accumulator.push(chunk);
+    if (this._accumulator.length >= this._batchSize) {
+      this.push(this._accumulator);
+      this._accumulator = [];
+    }
+    callback(null);
+  }
+
+  _flush(callback) {
+    if (this._accumulator.length) {
+      this.push(this._accumulator);
+      this._accumulator = null;
+    }
+    callback(null);
+  }
+}
+Batch.batch = Batch.make;
+Batch.make.Constructor = Batch;
+
+module.exports = Batch;