JavaScript trends that could be relevant in 2023 based on the trajectory of the language and the web development landscape up to that point:

1. TypeScript Adoption: TypeScript, a superset of JavaScript that adds static typing, has been steadily gaining popularity. In 2023, it’s likely that even more projects and companies will have adopted TypeScript due to its ability to catch bugs early and improve code quality.
2. Server-side JavaScript: With the rise of serverless architecture and Node.js becoming more mature, server-side JavaScript development could continue to grow. This might lead to more unified development stacks where the same language is used on both the front-end and back-end.
3. WebAssembly Integration: WebAssembly (Wasm) allows running code written in languages other than JavaScript in web browsers. JavaScript might continue to evolve with better integration of WebAssembly, enabling developers to build more performant and diverse web applications.
4. Progressive Web Apps (PWAs): PWAs provide a native app-like experience on the web. As browser support improves and user demand for seamless web experiences increases, PWAs could become a standard for building modern web applications.
5. Machine Learning and AI in JavaScript: JavaScript libraries and tools for machine learning and AI, such as TensorFlow.js, have been emerging. In 2023, these tools might become more mature, making it easier for developers to integrate AI capabilities into their web applications.
6. JAMstack Architecture: JAMstack (JavaScript, APIs, and Markup) architecture offers improved performance and security. Its adoption might continue to rise as developers seek efficient ways to build modern, scalable web applications.
7. Web Components: Web Components provide a way to create reusable UI elements encapsulated in their own HTML, CSS, and JavaScript. In 2023, they might gain more traction as a way to create modular and maintainable front-end code.
8. Focus on Accessibility: As the importance of web accessibility becomes more widely recognized, JavaScript frameworks and libraries might incorporate more built-in features to ensure accessible user interfaces.
9. Cross-platform Development: With the increasing variety of devices and platforms, tools that allow developers to build applications that work across different environments using JavaScript might continue to evolve.
10. ECMAScript Updates: The ECMAScript specification, which defines the syntax and features of JavaScript, typically sees regular updates. By 2023, there might have been several new features and improvements introduced to the language.

Remember, these trends are speculative and based on the trajectory of web development up until September 2021. For the most accurate and up-to-date information, it’s recommended to refer to current web development resources, blogs, and industry reports.