Using Angular to dynamically set data and labels for a bar chart

Question

Using Angular to dynamically set data and labels for a bar chart

My issue is with dynamically adding data to my bar chart dataset as it keeps returning undefined. Here's the current working version:

public barChartData: ChartDataSets[] = [
{ data: [], label: 'High' },
{ data: [], label: 'Medium' },
{ data: [], label: 'Low' }
];

this.barChartData[0].data.push(2);
console.log(this.barChartData[0].label);
console.log(this.barChartData[0].data);

The above code works, but it's not flexible enough because I don't know in advance how much data there will be. This led me to try a different approach:

public barChartData: ChartDataSets[] = [];
public barChartDataCount = 0;

for (let index = 0; index < this.tag.length; index++) {
  if(this.tag[index].type=='type')
  {
    this.barChartData[this.barChartDataCount].label=this.tag[index].name;
    this.barChartData[this.barChartDataCount].data.push(2);
    this.barChartDataCount++;
    this.numType++;
  }
}

However, when attempting this method, I encountered an error: ERROR TypeError: Cannot set properties of undefined (setting 'label')

angular typescript

Answer 1

Answer №1

The array this.barChartData is initially empty. If you attempt to access the first element using

this.barChartData[this.barChartDataCount]

, it will return null since the array is empty.

To populate the array, you can use the following code snippet:

for (let index = 0; index < this.tag.length; index++) {
  if(this.tag[index].type=='type')
  {
    this.barChartData.push({
        label: this.tag[index].name,
        data: 2
    })
    // additional logic here
  }
}

Answer 2

The array this.barChartData is initially empty. If you attempt to access the first element using

this.barChartData[this.barChartDataCount]

, it will return null since the array is empty.

To populate the array, you can use the following code snippet:

for (let index = 0; index < this.tag.length; index++) {
  if(this.tag[index].type=='type')
  {
    this.barChartData.push({
        label: this.tag[index].name,
        data: 2
    })
    // additional logic here
  }
}

Using Angular to dynamically set data and labels for a bar chart

Answer №1

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