Method update

src/Map.js:569–593

(ownerID, shift, keyHash, key, value, didChangeSize, didAlter)

  }

  update(ownerID, shift, keyHash, key, value, didChangeSize, didAlter) {
    const removed = value === NOT_SET;
    const keyMatch = is(key, this.entry[0]);
    if (keyMatch ? value === this.entry[1] : removed) {
      return this;
    }

    SetRef(didAlter);

    if (removed) {
      SetRef(didChangeSize);
      return; // undefined
    }

    if (keyMatch) {
      if (ownerID && ownerID === this.ownerID) {
        this.entry[1] = value;
        return this;
      }
      return new ValueNode(ownerID, this.keyHash, [key, value]);
    }

    SetRef(didChangeSize);
    return mergeIntoNode(this, ownerID, shift, hash(key), [key, value]);
  }
}

// #pragma Iterators