(In the past few years, Vue, React, and Angular have been the three mainstream front-end frameworks in China. In 2019, Vue is like an overwhelming dark horse, monopolizing the favor of front-end er, and Github Star ranking first also reflects the love of domestic developers for Vue. The column will systematically and carefully analyze the framework source code of Vue.js 3.0. In-depth analysis of the implementation principle of the kernel, and exploration of the design ideas behind the source code. On the one hand, it helps you consolidate your Vue.js development skills, on the other hand, it helps you understand source code analysis methods and programming ideas, and helps you understand the technical thinking logic behind excellent frameworks from the bottom.)