You only need this lines in order to see a legend in the chart.
<head>
<title>My A-Frame Scene</title>
<script src="https://aframe.io/releases/1.4.0/aframe.min.js"></script>
<script src="https://unpkg.com/aframe-charts-component/dist/aframe-charts-component.min.js"></script>
</head>
<body>
<!-- Aframe scene -->
<a-scene background="color: grey">
<!-- Aframe light -->
<a-light type="point" intensity="1" position="-2 10 10"></a-light>
<!-- Declaring chart component -->
<a-entity charts="type: pie; dataPoints: ../data/dataLegend.json; pie_radius: 3; show_legend_info: true; show_legend_position: -2 5 7;
show_legend_rotation: 0 35 0" position="5 0 0"></a-entity>
<!-- Aframe camera -->
<a-entity position="2 10 14" rotation="-30 15 0">
<a-camera position="3 -1 4" rotation="0 -1 0">
<a-cursor></a-cursor>
</a-camera>
</a-entity>
</a-scene>
</body>JSON input example
[
{"size": 1, "color": "#ff0000", "label": "USA"},
{"size": 1, "color": "#00ff00", "label": "Spain"},
{"size": 2, "color": "#0000ff", "label": "Mexico"},
{"size": 1.5, "color": "#000000", "label": "Japan"},
{"size": 4, "color": "#4CC3D9", "label": "India"}
]