Handle API to not receive value less than 0 (negative values)

I need to treat the API result so that I don’t receive values less than 0, I’ve been trying this way and so far I haven’t been able to:

private handleChart(data: Object): void {
    const series = [];

    for (const [key, value] of Object.entries(data)) {
      series.push({
        name: key,
        data: value,
        type: "line",
      });
    }
    
    if (series[0].data.length < 0) {
      delete series[0].data;
    }
    console.log(data );  

    this.plotChart(series);
  }

Original code:

private handleChart(data: Object): void {
    const series = [];

    for (const [key, value] of Object.entries(data)) {
      series.push({
        name: key,
        data: value,
        type: "line",
      });
    }

    this.plotChart(series);
  }