element-ui form表单中的form通过计算属性无法设置值

Question

<template>
    <el-form ref="form" :model="form" label-width="80px">
        {{JSON.stringify(form)}}
        <el-form-item label="活动名称" prop="name"><el-input v-model="form.name"></el-input></el-form-item>
        <el-form-item label="活动形式" prop="desc"><el-input type="textarea" v-model="form.desc"></el-input></el-form-item>
        <el-form-item>
            <el-button type="primary" @click="onSubmit">立即创建</el-button>
            <el-button @click="resetForm('form')">重置</el-button>
        </el-form-item>
    </el-form>
</template>
<script>
export default {
    name: 'test-form',
    data() {
        return {
            items: [
                {
                    name: 'name',
                    value: ''
                },
                {
                    name: 'desc',
                    value: 'desc'
                }
            ],
            
        };
    },
    computed: {
        form:{
            set() {},
            get () {
                let form = {};
                for (let index in this.items) {
                    const key = this.items[index];
                    form = Object.assign({}, form, {
                        [key.name]: key.value
                    });
                }
                return form;
            }
        }
    },
    created() {
        
        setTimeout( () => {
            
            this.$set(this.form,'name','name')
            
        },3000)
    },
    
    methods: {
        onSubmit() {
            console.log('submit!');
        },
        resetForm(formName) {
            this.$refs[formName].resetFields();
        }
    }
};
</script>