js调用push方法

Question

刚才有个考试，里面需要用到push方法，然而在编译的时候报了push is not a function的错误，请问这是为啥？

/**
 * @param {number[][]} edges
 * @return {number}
 */
var treeDiameter = function (edges) {
    if (edges.length === 0) return 0
    let graph = {}
    for (let i = 0; i < edges.length; i++) {
        if (graph[edges[i][0]]) {
            graph[edges[i][0]].push(edges[i][1])
        } else {
            graph[edges[i][0]] = [edges[i][1]]
        }
        if (graph[edges[i][1]]) {
            graph[edges[i][1]].push(edges[i][0])
        } else {
            graph[edges[i][1]] = [edges[i][0]]
        }
    }
    const res = []
    let max = 0
    const dfs = (cur, pre, path) => {
        if (!graph[cur] || (graph[cur].length === 1 && graph[cur][0] === pre)) {
            max = path.length > max ? path.length - 1 : max
            return
        }

        for (let i = 0; i < graph[cur].length; i++) {
            if (graph[cur][i] === pre) continue;
            let next = graph[cur][i]
            path.push(next)
            dfs(next, cur, path)
            path.pop()
        }
    }
    for (let i = 0; i <= edges.length; i++) {
        dfs(i, -1, [i])
    }
    return max

};

Answer 1

push是数组的方法，确定你使用push的对象是不是数组。