vue+ts 中使用 watch

import {Component, Vue, Watch} from 'vue-property-decorator';
private data = {};
private num = 0;

// 深层监听对象变化
@Watch('data ', {deep: true})
handleWatch() {
   this.drawPieChart();
}

@Watch('监听的数据名字')
方法名(newVal, oldVal) {
  console.log("newVal", newVal, "oldVal", oldVal)
};