uni-app supports multi-side output, and old projects before each platform can also be migrated to uni-app.
Guide to converting to uni-app for vue h5 projects: https://ask.dcloud.net.cn/article/36174
WeChat applet conversion uni-app guide and converter:https://ask.dcloud.net.cn/article/35786
wepy to uni-app converter:https://github.com/zhangdaren/wepy-to-uniapp
Another effective wepy to uni-app method: https://ask.dcloud.net.cn/article/39125
mpvue project (component) migration guide, example and resource summary: https://ask.dcloud.net.cn/article/34945