Uncaught (in promise) TypeError: Cannot read properties of undefined (reading ‘__composer’) 
Uncaught (in promise) TypeError: Cannot read properties of undefined (reading '__composer') vue-i18n.esm-bundler.js:1756 at Proxy.mounted (vue-i18n.esm-bundler.js:1756:52) at callWithErrorHandling (runtime-core.esm-bundler.js:155:22) at callWithAsyncErrorHandling (runtime-core.esm-bundler.js:164:21) at hook.__weh.hook.__weh (runtime-core.esm-bundler.js:2687:29) at flushPostFlushCbs (runtime-core.esm-bundler.js:358:32) at flushJobs (runtime-core.esm-bundler.js:403:9) 解决方案
在使用的时候`import { createI18n } from 'vue-i18n会报错，改成以下方式就好。
import {
createI18n } from 'vue-i18n/index';