如何将类的递归函数转换为redux动作？

Question

A recursive function shown bellow locates in a class. And, no state modification happens in the code section.

//delete target node and its subtree
function deleteSubTree(cur,nodearray){
    if(the node is not a leave) {
         //go to leaves
         deleteSubTree(cur.child,nodearray);
    }
    else{
        delete cur;
        if(cur.parent has a child) deleteSubTree(cur.parent,nodearray)
        else return;
    }
}

But because now I need to refactor my code to fit the redux framework, I need to turn this into a action. I think it should be converted to be

export function deleteSubTreeAction(node) {
    return (diespatch)=>{
         ....
        dispatch(deleteSubTreeAction(node.rChild));
         ...
    };
}

However, this looks quite weird. Any suggestions?

Answer 1

Split it into two actions:

1. DELETE_SUBTREE_START
2. DELETE_SUBTREE_END

Dispatch them like this:

// Helper function / side effect
function deleteSubTree(cur, nodearray, done){
    if(the node is not a leave) {
         //go to leaves
         deleteSubTree(cur.child, nodearray, done);
    }
    else {
        delete cur;
        if (cur.parent has a child) {
            deleteSubTree(cur.parent, nodearray, done)
        } else {
            return done();
        }
    }
}

// Action creator
export function deleteSubTreeAction(node) {
    return (dispatch) => {
        ...
        dispatch({ type: 'DELETE_SUBTREE_START' });
        deleteSubTree(
            node.rChild,
            ?, // not sure if you need the second argument here?
            () => dispatch({ type: 'DELETE_SUBTREE_END' })
        );
        ...
    };
}

This way the recursive function can signal when it's done() and can take as long as it needs. For performance, consider limiting the maximum tree depth though, which could dispatch something like DELETE_SUBTREE_ABORT .