Develop Reference

Recursive function in javascript that outputs JSON

In plain javascript, I am trying to create a function that will return a tree structure (json) of a folder, its subfolders and any files. I'm trying to achieve this using recursion.
The problem with the below code is that it stops after the first recursive call.
I know that in JS you do references, and I need to create a new object that I pass the values from the previous call to, but I am struggling to do so.
function fun(file, json) {
var tempJson = {
'name' : json.name || '',
'children' : obj.children || new Object()
};
if (file.type == 'file') {
tempJson.type = 'file';
tempJson.children = {}; // this will be empty, since there are no children
}
else {
tempJson.type = 'dir';
var listed = file.listFiles();
if (listed.length > 0) {
for each (var item in listed) {
tempJson.children = fun(item, tempJson);
}
} else {
tempJson.children = {};
}
}
return tempJson;
}
Example
From a directory structure like:
-root
--file1
--dir1
---file1.1
--dir2
I would like to get a json like:
{
name: 'root',
type: 'dir',
children : [
{
name: 'file1',
type: 'file',
children: {}
},
{
name: 'dir1',
type: 'dir',
children:
{
name: 'file1.1',
type: 'file',
children: {},
}
},
name: 'dir2',
type: 'dir',
children: {}
}
First call:
var object = new Object();
fun(rootdir, object);
Hope this makes sense.
Thanks!

As pointed out in the comments, children should be an array:
function fun(entry) {
var entryObj = { // construct the object for this entry
name: entry.name || "",
type: entry.type, // put the type here instead of using an if
children: [] // children must be an array
};
if(entry.type === "dir") { // if this entry is a directory
var childEntries = entry.listFiles(); // get its child entries
for(var childEntry of childEntries) { // and for each one of them
entryObj.children.push(fun(childEntry)); // add the result of the call of 'fun' on them to the children array
}
}
return entryObj;
}
Then call it like so:
var tree = fun(rootEntry);

Matching a string to one of many patterns and extracting data

I have a problem I want to solve with RegEx, or any other method if there is a better one. I've tried several ways to achieve the goal, but nothing really worked.
I have an array with endpoints:
const endpoints = [
{
id: 1,
url: "/api/items/:itemId"
},
{
id: 2,
url: "/api/users/:userName/delete"
},
{
id: 3,
url: "/api/users/:userName/edit"
}
];
And a request URL:
const url = "/api/users/max/edit";
Now what I want is to have a function which acts like this:
const rewrite = (url, endpoints) => {
// What is the best way to achieve the following return value:
return {
endpointId: 3,
values: {
userName: "max"
}
};
};
Explanation: The function should find the appropriate endpoint for the url. All parts of the endpoint url which start with a colon are not static, but should rather be replaced with values from the request url. In this case :userName should be replaced with max.
I've been in web development for some time now, but to be honest I've almost no clue how to solve such a problem.

const rewrite = (url, endpoints) => {
var doubledArray = Array.prototype.map.call(endpoints, function(el) {
return {
id: el.id,
url: el.url.split('/')
};
});
var parts = url.split('/');
var i = 0;
parts.forEach(function(element) {
doubledArray = doubledArray.filter(el => (element == el.url[i] || el.url[i].startsWith(':')));
i++;
});
return {
endpointId: doubledArray[0].id,
values: {
[`${doubledArray[0].url.filter(el => el.startsWith(':'))[0].substring(1)}`]: parts[doubledArray[0].url.findIndex(function (el) { return el.startsWith(':'); } )],
}
};
};

You can go through the endpoints making each .url into a RegExp to test the url against.
When a matching one is found, it is just a matter of extracting the needed part and making up an Object with the property name:
<script>
const myEndpoints = [
{
id: 1,
url: "/api/items/:itemId"
},
{
id: 2,
url: "/api/users/:userName/delete"
},
{
id: 3,
url: "/api/users/:userName/edit"
}
];
const myUrl = "/api/users/nermal/edit";
const rewrite = (url, endpoints) => {
for (let i = 0; i < endpoints.length; i++) {
var rep = new RegExp(":(\\w+)", "m");
var propName = rep.exec(endpoints[i].url);
var reu = new RegExp(endpoints[i].url.replace(propName[0], "(.*)"));
var a = reu.exec(url);
if (a !== null) {
var x = new Object;
x["endpointId"] = endpoints[i].id;
var y = new Object;
y[propName[1]] = a[1];
x["values"] = y;
return x;
}
}
return null;
};
var q = rewrite(myUrl, myEndpoints);
console.log(q);
console.log(q.values);
</script>
Outputs:
Object { endpointId: 3, values: {…} }
Object { userName: "nermal" }

How do I deal with an object sent into AngularJS controller?

In my controller I have a function that recieves an object from Java controller. My AngularJS variable is simple:
var self = this;
self.item = {};
And my function where I get the object:
function getItem() {
MyService.getItem(REST_SERVICE_URI)
.then(
function (d) {
self.item = d;
},
function (errResponse) {
console.error('Error while getting item');
}
);
}
Object that's received has rather complicated structure. It has id, name and list of child objects, who have also id and name fields. How do I get into this object's fields and list in the AngularJS controller? I tried loop though list using fucntion below to even count duplicate values but it didn't work. I tried even to include one more loop into it with outputing result in console, no effect. It only returns zeros.
var i = "SOME TEST NAME VALUE TO CHECK";
function getCount(i) {
var iCount = iCount || 0;
for (var el in self.item) {
console.log("let me see what are you: " + el);
if (el == i) {
iCount++;
}
}
return iCount;
}
The object I recieve is ok, I can see it content in Chrome using F12 - Network - Response or Preview.
added later:
On my page I test it like this
<tr class="my_item" ng-repeat="p in ctrl.item.children">
<span>getCount {{p.name}}: {{ctrl.getCount(p.name)}}</span>
</tr>
It displays p.name in the span btw. Java object structure is
public class Item {
private int id;
private String name;
List<Child> children = new ArrayList<>();
}
Child class is simple
public class Child {
private int id;
private String name;
}

As per your question, the content is complex and has recursive properties inside child content.
So you need to iterate on content recursively, inside one forEach loop.
See this example working Demo:
var myApp = angular.module('myApp', []);
myApp.controller('ExampleController', function() {
var vm = this;
vm.count = 0;
vm.searchTxt = "";
vm.getCount = function() {
vm.count = 0; //clear count before search
recursive(vm.content);
}
function recursive(dataArray) { //recursive function
dataArray.forEach(function(data) {
if (vm.searchTxt == data.name) { //match name property
vm.count = vm.count + 1;
}
if (data.child.length > 0) {
recursive(data.child); // call recursive function
}
});
}
vm.content = [{ //example content
id: 1,
name: 'one',
child: [{
id: 1.1,
name: 'new one',
child: [{
id: 1,
name: 'one',
child: []
}]
}]
}, {
id: 2,
name: 'two',
child: [{
id: 1.1,
name: 'new two',
child: []
}]
}]
});
<script src="https://code.angularjs.org/1.5.2/angular.js"></script>
<div ng-app="myApp" ng-controller="ExampleController as vm">
<input ng-model="vm.searchTxt" placeholder="ender search.." />
<br>
<button ng-click="vm.getCount()">Search</button>
<br>
<span>Match 'Name' count : {{vm.count}}</span>
</div>

unable to access function from another function using this within same object

I have the following:
$scope.option = {
generateID:function(){
return Math.random().toString(36).replace(/[^a-z]+/g, '').substr(0, 5);
},
values : [
{id:this.generateId()},
{id:this.generateId()},
{id:this.generateId()},
{id:this.generateId()}
],
markCorrect : function(option){
},
remove:function(option)
{
this.values = this.values.filter(function(value){return value.id!=option.id})
}
}
I always get a this.generateId is not a function error. I am pretty sure that i am missing something fundamental here!

It may be better to store the id generator function in a separate function so it is easier to reference:
function generateId = function() {
return Math.random().toString(36).replace(/[^a-z]+/g, '').substr(0, 5);
}
$scope.option = {
generateID: generateId,
values : [
{id: generateId()},
{id: generateId()},
{id: generateId()},
{id: generateId()}
],
markCorrect : function(option){
},
remove:function(option)
{
this.values = this.values.filter(function(value){return value.id!=option.id})
}
}

The primary issue is that you're trying to access properties of $scope.option in the middle of declaring it. Try doing something like this instead:
$scope.option = (function () {
function generateId () {
/* logic */
}
return {
values: [
{id: generateId()}
// ...
],
markCorrect: function () {},
remove: function () {}
};
}) ();
This is the 'revealing module pattern', i.e. a function that returns an object forming a closure on some other data or functionality.

There is a typo; rename generateID to generateId.

KnockOutJS trigger parent function on child subscribe

I am currently trying to learn KnockOutJS. I thought it would be a great idea to create a simple task-list application.
I do not want to write a long text here, let's dive into my problem. I appreciate all kind of help - I am new to KnockOutJS tho!
The tasks are declared as followed:
var Task = function (data) {
var self = this;
self.name = ko.observable(data.name);
self.status = ko.observable(data.status);
self.priority = ko.observable(data.priority);
}
And the view model looks like this
var TaskListViewModel = function() {
var self = this;
self.currentTask = ko.observable();
self.currentTask(new Task({ name: "", status: false, priority: new Priority({ name: "", value: 0 }) }));
self.tasksArr = ko.observableArray();
self.tasks = ko.computed(function () {
return self.tasksArr.slice().sort(self.sortTasks);
}, self);
self.sortTasks = function (l, r) {
if (l.status() != r.status()) {
if (l.status()) return 1;
else return -1;
}
return (l.priority().value > r.priority().value) ? 1 : -1;
};
self.priorities = [
new Priority({ name: "Low", value: 3 }),
new Priority({ name: "Medium", value: 2 }),
new Priority({ name: "High", value: 1 })
];
// Adds a task to the list
// also saves updated task list to localstorage
self.addTask = function () {
self.tasksArr.push(new Task({ name: self.currentTask().name(), status: false, priority: self.currentTask().priority() }));
self.localStorageSave();
self.currentTask().name("");
};
// Removes a task to a list
// also saves updated task list to localstorage
self.removeTask = function (task) {
self.tasksArr.remove(task);
self.localStorageSave();
};
// Simple test function to check if event is fired.
self.testFunction = function (task) {
console.log("Test function called");
};
// Saves all tasks to localStorage
self.localStorageSave = function () {
localStorage.setItem("romaTasks", ko.toJSON(self.tasksArr));
};
// loads saved data from localstorage and parses them correctly.
self.localStorageLoad = function () {
var parsed = JSON.parse(localStorage.getItem("romaTasks"));
if (parsed != null) {
var tTask = null;
for (var i = 0; i < parsed.length; i++) {
tTask = new Task({
name: parsed[i].name,
status: parsed[i].status,
priority: new Priority({
name: parsed[i].priority.name,
value: parsed[i].priority.value
})
});
self.tasksArr.push(tTask);
}
}
};
self.localStorageLoad();
}
What I want to do in my html is pretty simple.
All tasks I have added are saved to localStorage. The save function is, as you can see, called each time an element has been added & removed. But I also want to save as soon as the status of each task has been changed, but it is not possible to use subscribe here, such as
self.status.subscribe(function() {});
because I cannot access self.tasksArr from the Task class.
Any idea? Is it possible to make the self.tasksArr public somehow?
Thanks in advance!

Try this:
self.addTask = function () {
var myTask = new Task({ name: self.currentTask().name(), status: false, priority: self.currentTask().priority() })
myTask.status.subscribe(function (newValue) {
self.localStorageSave();
});
self.tasksArr.push(myTask);
self.localStorageSave();
self.currentTask().name("");
};