How to show Legend of Apex Charts (ReactJS) even if there is no series data available - reactjs

Question

I am using line-apex Charts in ReactJs. If there is no data available then legend for Y-Axis is invisible. And if data is available they will show up. I want legend to be displayed even if there is no data in series.
Alternatives I tried out: If there is no data in DB, send seriesData with 0 Values, it will show the point on the graph with 0 value and legend will be available. But, I want to get rid of that point.
getOptions() {
return {
chart: {
height: 200,
type: "line",
stacked: false,
},
colors: this.themes[this.props.theme],
dataLabels: {
enabled: false,
},
stroke: {
width: [3.5, 3.5],
},
xaxis: {
categories: this.props.xCategories,
labels: {
style: {
color: "#263238",
},
},
},
yaxis: [
{
axisTicks: {
show: true,
},
axisBorder: {
show: false,
},
labels: {
style: {
colors: this.themes[this.props.theme][0],
fontWeight: "bold",
},
},
tooltip: {
enabled: false,
}
},
{
seriesName: "Revenue",
opposite: false,
axisTicks: {
show: true,
},
axisBorder: {
show: false,
},
labels: {
style: {
colors: this.themes[this.props.theme][1],
fontWeight: "bold",
},
},
},
],
legend: {
position: "top",
horizontalAlign: "left",
offsetX: -15,
fontWeight: "bold",
}
}
}
And below is the render method:
render() {
return (
<div>
<Chart
options={this.getOptions()}
series={this.props.seriesData}
type='line'
/>
</div>
);
}

Answer 1

There are a few properties that determine whether the legend should be shown in different circumstances. There's information available in the ApexCharts documentation, but here's an overview:
showForSingleSeries
default: false
This will determine if the legend should be shown even if there is just one series being displayed on the graph.
showForNullSeries
default: true
This will determine whether series that contain only null values are hidden.
showForZeroSeries
default: true
This will determine whether series that contain only zero values are hidden.
In your case, you'll want to make sure first of all that the showForSingleSeries is set to true to ensure that the legend is always shown. Secondly, rather than returning a series that contains a zero value, you can return either an empty array or an array containing null elements.
Finally, in order for the legend to show up when using your code, I had to add a series property to the options object. This is because the legend won't display unless it has any series names to show - it doesn't know the names of the series you'll be providing it with unless you specify it.
var options = {
...
series: [
{
name: "Revenue",
data: []
}
]
...
}