递归函数返回后的函数调用

Question

I am having a recursive function in some service class to remove some json elements and once they are removed I have to call the callbacks registered for the updates.

My Code -

    var trimTree = function(){
    removeScripts(tree.children).then(function(){
      angular.forEach(callbacks, function(callback){
        //console.log(callback);
        console.log("Calling callbacks");
        callback();
      });
    });
  }
  function removeScripts(nodes){
    for(i=0;i<nodes.length;i++){
      if(nodes[i].type == 'script'){
        return nodes.splice(i, 1);
      }else{
        return removeScripts(nodes[i]);
      }
    }
  }

But its giving me error as TypeError: Cannot read property 'then' of undefined

Thanks

Answer 1

You're assuming removeScripts() returns a Promise, it does not. removeScripts() is sync, so just add statements after it normally.

Answer 2

You can try:

function removeScripts(nodes){
  var deferred = $q.defer();
  for(i=0;i<nodes.length;i++){
    if(nodes[i].type == 'script'){
      deferred.resolve(nodes.splice(i, 1));
    }else{
      deferred.reject(removeScripts(nodes[i]));
    }
  }
  return deferred.promise;
}

You need to use Deferred API .