res.Data.pipe不是函数错误消息

Question

我在Angular 6上持续收到以下错误：

core.js:1673 ERROR TypeError: res.Data.pipe is not a function

这是我的代码在这里：

this._prices.getHistoricalPrices(this.symbol, prefix, timeLimit, aggregate).subscribe(res => {
  if (environment.production === false) {
    console.log(res.Data);
    console.log(res.Data.length);
  }

  priceChart = res.Data.pipe(map(res.close));
  allDates = res.Data.pipe(map(res.time));

  if (environment.production === false) {
    console.log(priceChart);
  }

  cryptoDates = [];
  allDates.forEach(() => {
    const jsDate = new Date(res * 1000);
    cryptoDates.push(jsDate.toLocaleTimeString([], { day: 'numeric', month: 'short', hour: '2-digit', minute: '2-digit' }));
  });

  // Draw new chart

  this.chart = new Chart(canvasId, {
    type: 'LineWithLine',
    data: {
      labels: cryptoDates,
      datasets: [
        {
          data: priceChart,
          borderColor: '#60acf3',
          cubicInterpolationMode: 'monotone',
          fill: false
        }
      ]
    },
    options: this.chartOptions
  });
});

我包括了fuller segment here。我要创建的页面的示例是here。