前端代码在线执行—

 
<html>
<head>
    <script type="text/javascript" src="https://cdn.jsdelivr.net/npm/d3@7"></script>
</head>
<body>
<h3>D3 Nest API</h3>
<script>
    var data = [{"color": "red", "key": 1}, {"color": "green", "key": 2}, {"color": "blue", "key": 75}]
    var nest = d3.nest().key(function (d) {
        return d.color;
    }).entries(data);
    console.log(nest);
    var filter = nest.filter(function (d) {
        return d.key === 'red'
    })
    console.log(filter);
</script>
</body>
</html>