Vue 报错TypeError: this.$set is not a function 的解决方法

 methods: {
  textTranslate: function (text, to) {
 
   $.ajax({
    url: 'http://openapi.youdao./api',
    type: 'post',
    dataType: 'jsonp',
    data: {
     q: text,
     appKey: this.appKey,
     salt: this.salt,
     from: this.from,
     to: to,
     sign: md5(this.appKey + text + this.salt + this.key)
    },
    suess: function (data) {
     this.$set(this.$data, 'translatedText', data.translation[0])
    }
   })
  }
 }

 methods: {
  textTranslate: function (text, to) {
   let vm = this
   $.ajax({
    url: 'http://openapi.youdao./api',
    type: 'post',
    dataType: 'jsonp',
    data: {
     q: text,
     appKey: this.appKey,
     salt: this.salt,
     from: this.from,
     to: to,
     sign: md5(this.appKey + text + this.salt + this.key)
    },
    suess: function (data) {
     vm.$set(vm.$data, 'translatedText', data.translation[0])
    }
   })
  }
 }

suess: (data) => {
     this.$set(this.$data, 'translatedText', data.translation[0])
    }