JavaScript中的递归函数问题

Question

I am practicing using recursive functions to solve some simple javascript problems.

I am running into an issue with the following code,

var locate = function(arr,value){
    for (var i=0; i <arr.length; i++) {
        if(typeof arr[i]=== "string") {
            console.log("string is string");
            if(arr[i]=== value) {
                console.log("This should be true");
                return true;
            }
        }
        else {
            locate(arr[i], value);
        } 
    }
}
console.log(locate(['d', 'a',['e', 'g']], 'e'));

I cannot get this program to return true. It gets to the right part of the code, as it prints the statement above it.

Any help would be appreciated. I have been banging my head at this for a couple of hours now.

Edit-@Matt Burland pointed out the fact that you need to include a return statement when calling the recursive.

Answer 1

When you recurse, you need to return the value returned by the recursive call as you unwind.

So in your else clause, you need:

return locate(arr[i], value);

 var locate = function(arr,value){ for (var i=0; i <arr.length; i++) { if(typeof arr[i]=== "string") { console.log("string is string"); if(arr[i]=== value) { console.log("This should be true"); return true; } } else { return locate(arr[i], value); } } } alert(locate(['d', 'a',['e', 'g']], 'e'));