自动暴露子组件的方法，注意在TS下，需要自己声明类型，我这里全用any代替了

<template><el-button @click="getFocus">获得焦点</el-button><com ref="comRef" />
</template><script setup lang="ts">
import { ref } from 'vue'
import com from './components/com.vue'const comRef = ref(null);
const getFocus = () => {(comRef.value! as any).focus()
};
</script>

子组件

<template><el-input v-model="val" placeholder="请输入文本框" ref="inputRef" />
</template><script setup lang="ts">
import { ref } from 'vue'
import { InputInstance } from 'element-plus'const val = ref('');
const inputRef = ref<null | InputInstance>(null);defineExpose(new Proxy({}, {get(_target, key) {return (inputRef.value as any)?.[key];},has(_target, key) {return key in inputRef.value! as any;},
}))
</script>