[рони]

xcube,

const datas = [{name : 1, price : 100} , {name : 2, price : 45}, {name : 3, price : 400}],
      datab = [{name : 1, price : 5} , {name : 2, price  : 330}],
      obj = datas.reduce((obj, {name, price}) => (obj[name] = price, obj), {}),
      arr = [],
      dataz = datab.map(v => {
      const {name} = v ;
      v.цена = obj[name];
      if (v.price > v.цена)  arr.push(v);
      return v
      });


console.log(arr, dataz)