Method constructor

ch6-thread-pool/rpc-worker.js:6–24

(path, size = 0, strategy = 'roundrobin')

module.exports = class RpcWorkerPool {
  constructor(path, size = 0, strategy = 'roundrobin') {
    if (size === 0)     this.size = CORES; // <1>
    else if (size < 0)  this.size = Math.max(CORES + size, 1);
    else                this.size = size;

    if (!STRATEGIES.has(strategy)) throw new TypeError('invalid strategy');
    this.strategy = strategy; // <2>
    this.rr_index = -1;

    this.next_command_id = 0;
    this.workers = []; // <3>
    for (let i = 0; i < this.size; i++) {
      const worker = new Worker(path);
      this.workers.push({ worker, in_flight_commands: new Map() }); // <4>
      worker.on('message', (msg) => {
        this.onMessageHandler(msg, i);
      });
    }
  }
// THIS LINE SHOULD NOT APPEAR IN PRINT
  onMessageHandler(msg, worker_id) {
    const worker = this.workers[worker_id];