javascript - 如何编写递归来定位多维数组中的值

Question

我正在尝试编写一个递归函数来定位多维数组中的值。这是我到目前为止所尝试过的:

var locate = function (arr,value) {
    for (var i = 0; i < arr.length; i++) {
        if (arr[i] === value) {
            return true;
        } else if (Array.isArray(arr[i])) {
            locate(arr[i], value);
        }
    }
    return false;
}

但是，它不起作用:

console.log(locate(['a','b',['c','d',['e']]],'e'))
// => returns `false`, but should return `true`

我应该如何解决这个问题？

Answer 1

这是一个递归 DFS:

var locate = function (arr, value) {
    // start at the current array; we want to check every value
    for (var i = 0; i < arr.length; i++) {
        // if we've found our value, return immediately
        if (arr[i] === value) {
            return true;
        // if the element is an array, call locate on the element
        // and possibly return true
        // we don't want to return locate(arr[i], value) because
        // it could be found later on
        } else if (Array.isArray(arr[i]) && locate(arr[i], value)) {
            return true;
        } 
    }
    // reached the end of the current array, so return `false`
    // note, since we use `else if (... locate(arr[i], value)),
    // we won't stop the recursion before checking every possible value
    return false;
}