d3.js node.leaves()用法及代码示例

d3.js中的node.leaves()函数用于按遍历顺序返回给定层次数据的叶节点数组。

用法:

node.leaves();

参数：该函数不接受任何参数。

返回值：该函数返回一个数组。

注意：叶节点是没有子节点的那些节点。

下面给出的是上面给出的函数的一些例子。

范例1：

HTML

<!DOCTYPE html> 
<html lang="en"> 
  
<head> 
    <meta charset="UTF-8" /> 
    <meta name="viewport" path1tent= 
        "width=device-width, initial-scale = 1.0" /> 
    <script src="https://d3js.org/d3.v4.min.js"> 
    </script> 
</head> 
  
<body> 
    <script> 
        // Constructing a tree 
        var tree = { 
            name:"rootNode", 
            children:[ 
                { 
                    name:"child1_leaf1" 
                }, 
                { 
                    name:"child2", 
                    children:[ 
                        { 
                            name:"grandchild1", 
                            children:[ 
                                { name:"leaf2" } 
                            ] 
                        }, 
                    ] 
                }, 
                { 
                    name:"child3", 
                    children:[ 
                        { name:"leaf3" }, 
                        { name:"leaf4" }, 
                    ] 
                } 
            ] 
        }; 
  
        var obj = d3.hierarchy(tree); 
          
        // Leaf nodes of the above given tree 
        console.log("Leaf nodes are:"); 
        console.log(obj.leaves());         
    </script> 
</body> 
  
</html>

输出：

范例2：以下代码演示了访问叶节点的数据。

HTML

<!DOCTYPE html> 
<html lang="en"> 
  
<head> 
    <meta charset="UTF-8" /> 
    <meta name="viewport" path1tent= 
        "width=device-width, initial-scale = 1.0"/> 
    <script src="https://d3js.org/d3.v4.min.js"> 
    </script> 
</head> 
  
<body> 
    <script> 
        // Constructing a tree 
        var tree = { 
            name:"rootNode", 
            children:[ 
                { 
                    name:"child1_leaf1" 
                }, 
                { 
                    name:"child2", 
                    children:[ 
                        { 
                            name:"grandchild1", 
                            children:[ 
                                { name:"leaf2" } 
                            ] 
                        }, 
                    ] 
                }, 
                { 
                    name:"child3", 
                    children:[ 
                        { name:"leaf3" }, 
                        { name:"leaf4" }, 
                    ] 
                } 
            ] 
        }; 
  
        var obj = d3.hierarchy(tree); 
          
        // Leaf nodes of the above given tree are:
        console.log(" Accessing Leaf nodes:"); 
        let leafArr = obj.leaves(); 
        leafArr.forEach((e) => { 
            console.log(e.data); 
            console.log("depth:", e.depth); 
        })         
    </script> 
</body> 
  
</html>

输出：

相关用法

注：本文由纯净天空筛选整理自tarun007大神的英文原创作品 D3.js node.leaves() Function。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。