Develop Reference

Iterating over and comparing properties of two arrays of objects

I have set up a HBS helper which takes in two arrays of objects (users privileges). What I want to do is compare them and inject back into the template the privileges the user does and doesn't have.
Presently I can compare the names of the privileges with the following code:
hbs.registerHelper('selected', function(option, value){
var i;
var j;
var privName;
var userPriv;
var privObj = new Object();
var privArray = [];
for(i in option){
console.log('each ' + JSON.stringify(option[i]));
privName = option[i].privname;
for (y in value){
if(privName == value[y].privname){
userPriv = value[y].privname;
console.log('user has the following privileges', value[y].privname);
privObj = new Object();
privObj.name = userpriv;
privObj.id = value[y]._id;
privObj.state = 'selected';
privArray.push(privObj);
} else if (privName != value[y].privname){
console.log('user doesnt have priv ', privName);
privObj = new Object();
privObj.name = option[i].privname;
privObj.id = option[i].id;
privObj.state = '';
privArray.push(privObj);
}
}
}
console.log('privileges array ', privArray);
return privArray;
});
This works OK when the user only has one privilege, however when the user has more than one, for example two privileges, it returns the privileges twice. If the user has 3, thrice and so on. I know this is because the array is looping again because their are 2, 3 etc in the .length. However I can't seem to find an adequate solution.
Any help?
P.S. it would be nice if the Array.includes() method allowed you to search object properties.

The problem creating new objects the way you did is that for each property you add to your privilege-entity you will have to return to that function and set that property as well. You can instead just add/alter the state property of the existing objects:
hbs.registerHelper('selected', function(option, value) {
var names = option.map(function(opt) {
return opt.privname;
});
value.forEach(function(val) {
val.state = names.indexOf(val.privname) >= 0 ? 'selected' : '';
});
return value;
});
Basically:
The variable names is being mapped to be an array only with the privnames. You can check by using console.log(names).
The Array.forEach() function is helpful in this case because you just need to iterate over each object inside value and set its state-property.
To check if the privname exists, you just need to check the index in the previous names-mapped-array. For such a simple thing I used ternary operator (?:).
Finally, you return value, which is the array containing the objects you had updated.

Create variables based on array

I have the following array and a loop fetching the keys (https://jsfiddle.net/ytm04L53/)
var i;
var feeds = ["test_user_201508_20150826080829.txt:12345","test_user_list20150826:666","test_list_Summary20150826.txt:321"];
for (i = 0; i < feeds.length; i++) {
var feed = feeds[i];
alert(feed.match(/\d+$/));
}
The array will always contain different number of keys, What I would like to do is either use these keys as variables and assign the value after the : semicolon as its value or just create a new set of variables and assign the values found on these keys to them.
How can I achieve this? so that I can then perform some sort of comparison
if (test_user > 5000) {dosomething}
update
Thanks for the answers, how can I also create a set of variables and assign the array values to them? For instance something like the following.
valCount(feeds.split(","));
function valCount(t) {
if(t[0].match(/test_user_.*/))
var testUser = t[0].match(/\d+$/);
}
Obviously there is the possibility that sometimes there will only be 1 key in the array and some times 2 or 3, so t[0] won't always be test_user_
I need to somehow pass the array to a function and perform some sort of matching, if array key starts with test_user_ then grab the value and assign it to a define variable.
Thanks guys for all your help!

You can't (reasonably) create variables with dynamic names at runtime. (It is technically possible.)
Instead, you can create object properties:
var feeds = ["test_user_201508_20150826080829.txt:12345","test_user_list20150826:666","test_list_Summary20150826.txt:321"];
var obj = {};
feeds.forEach(function(entry) {
var parts = entry.split(":"); // Splits the string on the :
obj[parts[0]] = parts[1]; // Creates the property
});
Now, obj["test_user_201508_20150826080829.txt"] has the value "12345".
Live Example:
var feeds = ["test_user_201508_20150826080829.txt:12345","test_user_list20150826:666","test_list_Summary20150826.txt:321"];
var obj = {};
feeds.forEach(function(entry) {
var parts = entry.split(":");
obj[parts[0]] = parts[1];
});
snippet.log(obj["test_user_201508_20150826080829.txt"]);
<!-- Script provides the `snippet` object, see http://meta.stackexchange.com/a/242144/134069 -->
<script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script>

You can do it like this, using the split function:
var i;
var feeds = ["test_user_201508_20150826080829.txt:12345","test_user_list20150826:666","test_list_Summary20150826.txt:321"];
for (i = 0; i < feeds.length; i++) {
var feed = feeds[i];
console.log(feed.split(/[:]/));
}
This outputs:
["test_user_201508_20150826080829.txt", "12345"]
["test_user_list20150826", "666"]
["test_list_Summary20150826.txt", "321"]

Use the split method
var feeds = ["test_user_201508_20150826080829.txt:12345","test_user_list20150826:666","test_list_Summary20150826.txt:321"];
feedMap = {}
for (i = 0; i < feeds.length; i++) {
var temp = feeds[i].split(':');
feedMap[temp[0]] = temp[1];
}
Yields:
{
"test_user_201508_20150826080829.txt":"12345",
"test_user_list20150826":"666",
"test_list_Summary20150826.txt":"321"
}
And can be accessed like:
feedMap["test_user_201508_20150826080829.txt"]
Here is a codepen

it is not very good idea but if you really need to create variables on-the-run here's the code:
for (i = 0; i < feeds.length; i++)
{
var feed = feeds[i];
window[feed.substring(0, feed.indexOf(":"))] = feed.match(/\d+$/);
}
alert(test_user_201508_20150826080829)
Of course you cannot have any variable-name-string containing banned signs (like '.')
Regards,
Michał

Javascript Getting value from exact field from associative array

I have an associative array - indexed by dates. Every element holds another array.
[03/16/2015: Array[3], 03/17/2015: Array[3], 03/18/2015: Array[3], 03/19/2015: Array[3]]
I created it with this code:
array[cellDate][i]=cellText;
How can I get the value for example from cell 03/16/2015 array[2] ??
var text=array['03/16/2015'][2];
With this line of code I got an error.
EDIT:
http://www.traineffective.com/schedule/
I store in that array title of blocks dropped in the schedule (title of block of 'empty' value if cell is empty)
What I want to achive is remeber the order of the blocks for particular weeks , and when user changes week with arrows it loads block based on date withdrowed from array.
Code where I create array :
function saveWeekToArray(array){
var cellDate;
var cellText;
var tmpText;
var i;
workoutsTD.each(function(){
cellDate=$(this).attr("data-day");
array[cellDate]=['','',''];
i=0;
$(this).children('.workout-cell').each(function(){
if (!$(this).hasClass('workout-cell-empty')){
cellText=$(this).find('span').text();
array[cellDate][i]=cellText;
} else {
array[cellDate][i]='empty';
}
i++
});
});
}
Code where I load data from array (One with the error )
function loadBlocksFromArray(array){
var cellDate;
var cellText;
var tmpText;
var i;
workoutsTD.each(function(){
cellDate=$(this).attr("data-day");
i=0;
$(this).children('.workout-cell').each(function(){
if ((array[cellDate][i])!='empty'){
cellText=array[cellDate][i];
$(this).append(createBlock(cellText));
$(this).removeClass('workout-cell-empty');
}
i++;
});
});
}
When you will click sumbit button in console log you will see the structure of array.
I got error while changing the week its :
enter code hereUncaught TypeError: Cannot read property '0' of undefined

In Javascript, there is no concept of an associative array. You either have arrays (which are indexed by numbers) or you have Objects (whose elements are indexed by strings).
What you instead want is an object containing all of your arrays. For example:
var data = {
'3/4/2015' : ['val1', 'val2', 'val3'],
'3/8/2015' : ['val1', 'val2', 'val3']
};
Then you can access your elements in the way that you want:
var ele = data['3/4/2015'][1];

https://jsfiddle.net/x9dnwgwc/
That is the effect what I wanted achive. Thanks for hint Harvtronix!
var jsonObj = { workout : {} }
var i;
var k;
var workoutArray = [];
for(i=1; i<=7; i++){
var newWorkout = i+ "/12/2015";
for (k=0; k<=2; k++){
var newValue = "workoutTitle" + k;
workoutArray[k]=newValue;
}
jsonObj.workout[newWorkout]=workoutArray;
}
console.log(jsonObj);
for(i=1; i<=7; i++){
var newWorkout = i+ "/12/2015";
var tmpArray= jsonObj.workout[newWorkout];
console.log(tmpArray);
}

Why this json swap code does not work?

I have this fun :
swapjson = function (j1,j2)
{ var jj = JSON.parse(JSON.stringify(j1));
j1 = JSON.parse(JSON.stringify(j2));
j2 = jj;
}
I have also:
var myjson1 = {'x':1000, 'y':1000};
var myjson2 = {'x':2000, 'y':-2000};
swapjson (myjson1,myjson2);
console.log myjson1.x
1000 ?????
And I discover that inside the swapjson function the swap is made but not after call.
What is happen ? I dont understand what I'm doing bad...
Any help would be appreciated.

You can't replace the entire object like that, as the object itself isn't passed by referenced.
You can however change properties of the object passed, and it will stick, as a copy of the object is passed in.
So instead of parsing to strings and back to objects you can just iterate over the two objects keys, and replace one by one
swapjson = function (j1, j2) {
var temp = {};
for (key in j1) {
temp[key] = j1[key];
delete(j1[key]);
}
for (key in j2) {
j1[key] = j2[key];
delete(j2[key]);
}
for (key in temp) {
j2[key] = temp[key];
}
}
FIDDLE

You copy the value of myjson1 (which is a reference to an object and nothing to do with JSON) into j1, and the value of myjson2 into j2.
Then you overwrite the value of j1 and the value of j2.
You never change the values of myjson1 or myjson2.

Modify a global variable based on an object property

I'm trying to learn object oriented javascript and ran into the following problem:
I have an object constructor (is that the right term?) like this:
function itemCreator(itemName, itemType, itemPositionX, itemPositionY) {
this.itemName = itemName;
this.itemType = itemType;
this.itemPositionX = itemPositionX;
this.itemPositionY = itemPositionY;
allItems.push(this); //store all items in a global variable
}//end itemCreator;
//then I use it to create an object
megaRocket = new itemCreator (
'megarocket',
'item_megarocket',
108,
475
)
Now I realised I also need to map these objects to modify different global variables based on which "itemType" the object has. This is where I am stuck. How can I make a global variable that only objects with a specific itemType property can modify?
For example I would like to create an object that increments a variable called amountOfMegarockets, but only if the itemType for that object is "item_megarocket".
I later plan on looping an array of these items to see if player object touches them (to collect the item):
function checkForItems(){
var itemLen =allItems.length;
for (i=0; i < itemLen; i++){
var itemObject = allItems[i];
if ( //checking for "collisions" here
(ship.x < (itemObject.itemBitmap.x + itemObject.size) && (ship.x + shipWidth) > itemObject.itemBitmap.x) &&
(ship.y < (itemObject.itemBitmap.y + itemObject.size) && (ship.y + shipWidth) > itemObject.itemBitmap.y)
){
itemObject.actor.y = -500; //just removing the item from canvas here (temporary solution)
// Here comes pseudo code for the part that I'm stuck with
variableBasedOnItemObject.itemType++;
}
I hope my explanation makes sense to someone!
EDIT:
Bergi's answer makes most sense to me, but I can't get the syntax right. Here's how I'm trying to use Bergi's code:
var amounts = {},
allItems = [];
function itemCreator(itemName, itemType, itemPositionX, itemPositionY) {
this.itemName = itemName;
this.itemType = itemType;
this.itemPositionX = itemPositionX;
this.itemPositionY = itemPositionY;
(amounts[itemType]=2); // this is different from bergi's example because I need to set the initial value of the item to two
//I also shouldn't increase the item amount on creation of the item, but only when it's specifically called from another function
this.increaseCount = amounts[itemType]++; //this should IMO increase the itemType amount inside the amounts object when called, but it doesn't seem to work
}
//creating the object the way bergi suggested:
allItems.push(new itemCreator('shootUp001', 'item_up', 108, 475));
Now here's the problematic part:
function checkForItems(){
var itemLen =allItems.length;
for (i=0; i < itemLen; i++){
var itemObject = allItems[i];
if ( my condition here)
){
//code below is not increasing the value for the current itemType in the amounts object.
//Probably a simple syntax mistake?
itemObject.itemType.increaseCount;
}
}
}
Why is my call of itemObject.itemType.increaseCount; not increasing the value of amounts.itemType?

Increment a global variable called amountOfMegarockets, but only if the itemType for that object is "item_megarocket".
Don't use a global variable for each of those item types. Do use one object (in global or local scope) which counts the amouts of each type on its properties.
var amounts = {},
allItems = [];
function Item(itemName, itemType, itemPositionX, itemPositionY) {
this.itemName = itemName;
this.itemType = itemType;
this.itemPositionX = itemPositionX;
this.itemPositionY = itemPositionY;
amounts[itemType]++ || (amounts[itemType]=1); // count by type
allItems.push(this); // store all items
}
Notice that I wouldn't put all Item instances in an array by default, better omit that line and let it do the caller:
allItems.push(new Item('megarocket', 'item_megarocket', 108, 475));

you can do some things like
(function (global) {
// create a scope
var allItems = [];
global.itemCreator = function(itemName, itemType, itemPositionX, itemPositionY) {
this.itemName = itemName;
this.itemType = itemType;
this.itemPositionX = itemPositionX;
this.itemPositionY = itemPositionY;
allItems.push(this); //store all items in a global variable
}//end itemCreator;
})(this);
this will work. but seriously dont complicate too mutch your code juste to make private var. if someone want to cheat using debugger he will always found a way to do it.
---- edit
If you juste want access to global var base on itemType you can do some thing like:
function checkForItems(){
var itemLen =allItems.length;
for (i=0; i < itemLen; i++){
var itemObject = allItems[i];
if ( //checking for "collisions" here
(ship.x < (itemObject.itemBitmap.x + itemObject.size) && (ship.x + shipWidth) > itemObject.itemBitmap.x) &&
(ship.y < (itemObject.itemBitmap.y + itemObject.size) && (ship.y + shipWidth) > itemObject.itemBitmap.y)
){
itemObject.actor.y = -500; //just removing the item from canvas here (temporary solution)
// Here comes pseudo code for the part that I'm stuck with
if (window[itemObject.itemType + "Data"])) {
variableBasedOnItemObject.itemType++;
} else {
window[itemObject.itemType + "Data"] = {
itemType: 1
}
}
}
}
}