'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});

var _stream = require('stream');

// Discards "bytesToDiscard" bytes
class DiscardStream extends _stream.Transform {
  constructor() {
    let bytesToDiscard = arguments.length <= 0 || arguments[0] === undefined ? 0 : arguments[0];

    super();
    this.bytesToDiscard = bytesToDiscard;
    this.byteCount = 0;
    this.done = false;
  }
  _transform(chunk, encoding, cb) {
    if (this.done) return cb(null, chunk);

    this.byteCount += chunk.length;

    if (this.byteCount > this.bytesToDiscard) {
      this.done = true;
      const bytesToKeep = this.byteCount - this.bytesToDiscard;
      const firstChunk = chunk.slice(-bytesToKeep);
      return cb(null, firstChunk);
    }
    cb(null);
  }
}

exports.default = DiscardStream;