导出函数中的 javascript 递归 : not a function

Question

常年新手问题:如何修复这个“不是函数”错误:

exports.height = (input) => {
    function height(node, height) {
        if (node.left) {
            if (height > maxHeight) {
                maxHeight = height;
            }
            **height(node.left, height+1); // <-- Says "Not a function"**
        }
    }

    var maxHeight = 0;
    height( input, 0 ); // <--- This works fine.

    return maxHeight;
}

说，类型错误:高度不是函数

  at height (BinarySearchTree.js:53:5)

谢谢! 尼尔什

Answer 1

您不小心遮蔽了您的height变量

function height(node, <b>height</b>) {
    if (node.left) {
        if (height > maxHeight) {
            maxHeight = height;
        }
        height(node.left, height+1);
    }
}

var maxHeight = 0;
height( input, <b>0</b> ); // 0 is obviously not a function ^_^

尝试将 height 参数重命名为 h

function height(node, <b>h</b>) {
    if (node.left) {
        if (<b>h</b> > maxHeight) {
            maxHeight = <b>h</b>;
        }
        <b>return</b> height(node.left, <b>h</b>+1); // don't forget your return
    }
}

var maxHeight = 0;
height( input, 0 );

尽管如此，您可能需要重新考虑您的功能

function height (node) {
  if (node === undefined)
    return -1;
  else
    return Math.max(height(node.left), height(node.right)) + 1;
}