Vue.js, also known as Vue, and pronounced view, was created by Evan You and was released in the beginning of 2014. Originally, Evan had been working with AngularJS a lot, so many people argue that Vue very much resembles AngularJS.
Like React, it features a lightweight adoptable architecture, and thus it can be more easily embedded and integrated with existing apps and other technologies. Additionally, Vue is essentially a view engine, focusing on building components. Even when compared to React, Vue is less opinionated, and is actually more flexible in how you build components, in addition to offering supporting libraries that are maintained officially by the Vue team alongside its core Vue framework product.
Vue is constantly growing and gaining popularity quite steadily. Being a flexible framework focusing on component with support for MVC-style programming, it is often considered the middle ground in the spectrum between Angular and React.