npm ecosystem is crucial for the JavaScript community and its development is significantly influenced by the opinions and feedback of core software developers.Many software developers have utilized social media, such as Twitter, to share community-related information and their views. However, the communication between npm developers via Twitter in terms of topics, nature, and sentiment have not been analyzed.This study conducts an empirical analysis of tweets by core software developers related to the npm ecosystem to understand their perceptions and opinions better. A dataset of tweets was collected and analyzed using qualitative analysis techniques to identify the topic of tweets, their nature and their sentiments. Our study demonstrated that most tweets belong to the package management category followed by notifications and community-related information.The most frequently discussed topics among core software developers in the package management category are usage scenarios. It appears that developers use a variety of approaches, with information tweets dominating, followed by questions and answers.Additionally, the sentiment analysis revealed that developers express more positive sentiments towards notification and community-related discussion while expressing more neutral opinions towards the package ecosystem discussion category. This case study provides valuable insights into the perceptions and opinions of core software developers regarding the npm ecosystem and can inform future development and decision-making.