AngularJs pushing multiple values from array to another with databinding refreshing - javascript

I am getting an array from the server which can contain 0..n elements in an array. I then add that to array I use locally for databinding (basically cache data in client). When doing it this way databiding works without any problems:
for (var i = 0 ; i < data.Result.length ; i++) {
scope.cachedData.push(data.Result[i]);
}
Meaning - view refreshes, everything works. But when I try: scope.cachedData.concat(data.Result); it won't work. Why is that?

If you want to push everything in a single instruction use apply without breaking the reference to scope.cachedData
Array.prototype.push.apply(scope.cachedData, data.Result);
Also, I know this is a little bit off topic but if you want to insert at a specific index you can use splice with apply
// I definitely want to prepend to my array here
var insertionIndex = 0,
// we don't want to delete any elements here from insertionIndex
deleteCount = 0;
// Because we use apply the second argument is an array
// and because splice signature is (startIndex, noOfElementsToDelete, elementsToInsert)
// we need to build it
Array.prototype.splice.apply(scope.cachedData, [insertionIndex, deleteCount].concat(data.Result));
Imagine your array scope.cachedData = [3,4]; and data.Result = [1,2];, with the code above scope.cachedData will become [1,2,3,4].

Related

What is the best way to itterate over key value pairs nested in an index using javascript?

I am trying to sort sets of associated key value pairs. They look like this:
{"word":"a","votes":9326,"userMade":"FALSE","limiter":"FALSE"},
But organized into labeled subsets of preferably a string or perhaps an index if necessary.
The data-set is a vote-per-use table of most used english words being parsed into pages.
I will be appending them as text to other html elements due to the constraints my use case, makes it a bit tricky, however, for an example I could work with a simple console.log of the page value followed by the console.log of every word value stored within that page. I need the order preserved. so probably indexed. I will also need to be able to sort each page by the votes value, but I think I can figure the rest out for that.
I have found tutorials on how to search through key-value pairs, but I cannot find how to do all of the following with one solution:
A: access the value of word
B: maintain the order of the data-set, allowing me to append them to the matching html element
C: allows me the opportunity to change which set of elements I am appending to when i have finished looping through a single member of the parent index (the one recording the page)
I imagine it is some combination of for/of and for/in, but I'm getting a headache. Please help?
addl info:
function would run at app startup or when the dataset being examined is changed.
function would take a large dataset filled with around 200 page number values, each with 60+ sets of data like the one listed above, the contents of a single page index for example:
{"word":"a","votes":9326,"userMade":"FALSE","limiter":"FALSE"},
{"word":"aaron","votes":4129,"userMade":"FALSE","limiter":"FALSE"},
{"word":"abandoned","votes":1289,"userMade":"FALSE","limiter":"FALSE"},
{"word":"abc","votes":5449,"userMade":"FALSE","limiter":"FALSE"},
{"word":"aberdeen","votes":641,"userMade":"FALSE","limiter":"FALSE"},
{"word":"abilities","votes":2210,"userMade":"FALSE","limiter":"FALSE"},
{"word":"ability","votes":7838,"userMade":"FALSE","limiter":"FALSE"},
{"word":"able","votes":8649,"userMade":"FALSE","limiter":"FALSE"},
{"word":"aboriginal","votes":1837,"userMade":"FALSE","limiter":"FALSE"},
{"word":"abortion","votes":3232,"userMade":"FALSE","limiter":"FALSE"},
{"word":"about","votes":9295,"userMade":"FALSE","limiter":"FALSE"},
{"word":"above","votes":8818,"userMade":"FALSE","limiter":"FALSE"},
{"word":"abraham","votes":867,"userMade":"FALSE","limiter":"FALSE"},
{"word":"abroad","votes":4969,"userMade":"FALSE","limiter":"FALSE"},
{"word":"abs","votes":2415,"userMade":"FALSE","limiter":"FALSE"},
{"word":"absence","votes":4934,"userMade":"FALSE","limiter":"FALSE"},
{"word":"absent","votes":2937,"userMade":"FALSE","limiter":"FALSE"},
{"word":"absolute","votes":5251,"userMade":"FALSE","limiter":"FALSE"},
{"word":"absolutely","votes":5936,"userMade":"FALSE","limiter":"FALSE"},
{"word":"absorption","votes":285,"userMade":"FALSE","limiter":"FALSE"},
{"word":"abstract","votes":7946,"userMade":"FALSE","limiter":"FALSE"},
{"word":"abstracts","votes":1907,"userMade":"FALSE","limiter":"FALSE"},
{"word":"abuse","votes":7238,"userMade":"FALSE","limiter":"FALSE"},
{"word":"academic","votes":7917,"userMade":"FALSE","limiter":"FALSE"},
{"word":"academics","votes":1706,"userMade":"FALSE","limiter":"FALSE"},
{"word":"academy","votes":6755,"userMade":"FALSE","limiter":"FALSE"},
{"word":"acc","votes":6469,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accent","votes":1020,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accept","votes":7547,"userMade":"FALSE","limiter":"FALSE"},
{"word":"acceptable","votes":4907,"userMade":"FALSE","limiter":"FALSE"},
{"word":"acceptance","votes":7273,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accepted","votes":7684,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accepting","votes":1789,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accepts","votes":1535,"userMade":"FALSE","limiter":"FALSE"},
{"word":"access","votes":9031,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accessed","votes":2932,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accessibility","votes":5702,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accessible","votes":5662,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accessing","votes":2096,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accessories","votes":8875,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accessory","votes":5661,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accident","votes":5664,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accidents","votes":2991,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accommodate","votes":1807,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accommodation","votes":8059,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accommodations","votes":3885,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accompanied","votes":2532,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accompanying","votes":664,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accomplish","votes":1070,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accomplished","votes":2419,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accordance","votes":6434,"userMade":"FALSE","limiter":"FALSE"},
{"word":"according","votes":8282,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accordingly","votes":3003,"userMade":"FALSE","limiter":"FALSE"},
{"word":"account","votes":8996,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accountability","votes":3029,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accounting","votes":7459,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accounts","votes":7507,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accreditation","votes":1605,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accredited","votes":3027,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accuracy","votes":6779,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accurate","votes":6427,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accurately","votes":1493,"userMade":"FALSE","limiter":"FALSE"},
{"word":"accused","votes":2853,"userMade":"FALSE","limiter":"FALSE"},
{"word":"acdbentity","votes":1389,"userMade":"FALSE","limiter":"FALSE"},
and the output would ultimately append the value paired with each word to a specific button through iteration, but also sorted by the page value.
each page is a set of buttons in a 3d object that looks like this:
the text is appended to each button which in turn is a 3d object embeded in an html object using aframe. I can make the appending code.
You can use Object.entries() to get the key value pairs of an object.
var words = [
{"word":"a","votes":9326,"userMade":"FALSE","limiter":"FALSE"},
{"word":"aaron","votes":4129,"userMade":"FALSE","limiter":"FALSE"}
];
words.forEach((wordEntry) => {
var keyValuePairs = Object.entries(wordEntry);
keyValuePairs.forEach((kv) => {
console.log(`key: ${kv[0]} value: ${kv[1]}`);
});
});
my latest attempt looks like this:
for (let p=1; p<129; p++){
for (let b=1; b<68; b++){
let pTpl = (p).toLocaleString(undefined, {minimumIntegerDigits: 3});
let bDbl = (b).toLocaleString(undefined, {minimumIntegerDigits: 2});
var `#fCont${pTpl}${bDbl}` = document.createElement('a-text');
`fCont${pTpl}${bDbl}`.setAttribute('value', 'engWordLib[p,b,0]');
`fCont${pTpl}${bDbl}`.setAttribute('votes', 'engWordLib[p,b,1]');
`fCont${pTpl}${bDbl}`.setAttribute('userMade', 'engWordLib[p,b,2]');
`fCont${pTpl}${bDbl}`.setAttribute('limiter', 'engWordLib[p,b,3]');
`fCont${pTpl}${bDbl}`.setAttribute('visible', 'false');
`fBtn${bDbl}`.appendChild(`#fCont${pTpl}${bDbl}`)
}
}
please note that I havent checked this for errors. I still think this code is to WET and I would prefer the key names for the properties be preserved in the datastructure rather than tacked on when it's appended to the page. I guess I could add a dimension to the array.... seems kind of messy when an object property value has the key value pairs right in it. cant get the iteration of objects in an array down though.... Will continue to persue a cleaner method.

for..in loop loops over non-numeric indexes “clean” and “remove”

This is something very basic I might be missing here but I haven't seen such result till now.
I have a for loop where options.headers.length is 3. And in for loop I am dynamically creating a table header. Ideally this loop should run three times for 0 1 and 2 but when I have printed index it's printing 0,1,2,clean and remove. I haven't seen clean and remove as indexes. I know this information is not sufficient enough but if you have any clue please suggest. something might be overriding this is all I am concluded too after my debugging.
for (index in options.headers)
if you don't want to iterate clean and remove then change the loop to:
for (var i=0; i< options.headers.length;i++){
//use i for getting the array data
}
if you use for (index in options.headers) it will iterate for non-numeric keys also.
don use just index (as that is = window.index = global = bad) use var index
(read more here https://www.google.pl/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=globals+javascript+bad)
you have to check does the array has it as own property or maybe its some function (more after answer)
for (var index in options.headers) {
if (options.headers.hasOwnProperty(index) {
// code here
}
}
more about #2:
let's say we have
var array = [0,1,2,3];
and besides that, extending array with function (arrays can have functions in javascript and strings too)
Array.prototype.sayHello = function() {
alert('Hello');
};
then your loop would print sayHello as part of the array, but that's not it's own property, only the arrays
I assume that options.headers is an Array?
This happens when you (or some framework you load) adds methods to the Array prototype. The "for in" loop will enumerate also these added methods. Hence you should do the loop for an array with:
for (var i = 0; i < options.headers.length; i++)
That way you will only get the real values instead of added methods.

Filter/Search JavaScript array of objects based on other array in Node JS

i have one array of ids and one JavaScript objects array. I need to filter/search the JavaScript objects array with the values in the array in Node JS.
For example
var id = [1,2,3];
var fullData = [
{id:1, name: "test1"}
,{id:2, name: "test2"}
,{id:3, name: "test3"}
,{id:4, name: "test4"}
,{id:5, name: "test5"}
];
Using the above data, as a result i need to have :
var result = [
{id:1, name: "test1"}
,{id:2, name: "test2"}
,{id:3, name: "test3"}
];
I know i can loop through both and check for matching ids. But is this the only way to do it or there is more simple and resource friendly solution.
The amount of data which will be compared is about 30-40k rows.
This will do the trick, using Array.prototype.filter:
var result = fullData.filter(function(item){ // Filter fulldata on...
return id.indexOf(item.id) !== -1; // Whether or not the current item's `id`
}); // is found in the `id` array.
Please note that this filter function is not available on IE 8 or lower, but the MDN has a polyfill available.
As long as you're starting with an unsorted Array of all possible Objects, there's no way around iterating through it. #Cerbrus' answer is one good way of doing this, with Array.prototype.filter, but you could also use loops.
But do you really need to start with an unsorted Array of all possible Objects?
For example, is it possible to filter these objects out before they ever get into the Array? Maybe you could apply your test when you're first building the Array, so that objects which fail the test never even become part of it. That would be more resource-friendly, and if it makes sense for your particular app, then it might even be simpler.
function insertItemIfPass(theArray, theItem, theTest) {
if (theTest(theItem)) {
theArray.push(theItem);
}
}
// Insert your items by using insertItemIfPass
var i;
for (i = 0; i < theArray.length; i += 1) {
doSomething(theArray[i]);
}
Alternatively, could you use a data structure that keeps track of whether an object passes the test? The simplest way to do this, if you absolutely must use an Array, would be to also keep an index to it. When you add your objects to the Array, you apply the test: if an object passes, then its position in the Array gets put into the index. Then, when you need to get objects out of the Array, you can consult the index: that way, you don't waste time going through the Array when you don't need to touch most of the objects in the first place. If you have several different tests, then you could keep several different indexes, one for each test. This takes a little more memory, but it can save a lot of time.
function insertItem(theArray, theItem, theTest, theIndex) {
theArray.push(theItem);
if (theTest(theItem)) {
theIndex.push(theArray.length - 1);
}
}
// Insert your items using insertItem, which also builds the index
var i;
for (i = 0; i < theIndex.length; i += 1) {
doSomething(theArray[theIndex[i]]);
}
Could you sort the Array so that the test can short-circuit? Imagine a setup where you've got your array set up so that everything which passes the test comes first. That way, as soon as you hit your first item that fails, you know that all of the remaining items will fail. Then you can stop your loop right away, since you know there aren't any more "good" items.
// Insert your items, keeping items which pass theTest before items which don't
var i = 0;
while (i < theArray.length) {
if (!theTest(theArray[i])) {
break;
}
doSomething(theArray[i]);
i += 1;
}
The bottom line is that this isn't so much a language question as an algorithms question. It doesn't sound like your current data structure -an unsorted Array of all possible items- is well-suited for your particular problem. Depending on what else the application needs to do, it might make more sense to use another data structure entirely, or to augment the existing structure with indexes. Either way, if it's planned carefully, will save you some time.

How can I store values from one array to another array using 'for' loop

I am trying to create number of arrays like _temp0[],_temp1[],_temp2[] so on and I want to store values of data[] in it.
so value of data[0] goes in array_temp0[] after splitting,
data[1] goes in _temp1[] and so on
to elaborate more-
If value of data[0] is string a,b,c
then array _temp0[] should be
_temp0[0]=a
_temp0[1]=b
_temp0[2]=c
I wrote this function
for(var k=0;k<data.length-1;k++)
{
window['_temp' + k] = new Array();
alert("actual data -- >"+data[k]);
'_temp'+k= data[k].split(',');
alert("data after split -- >"_temp[k]);
}
but it is not working, how do I solve it?
You can do the same using javascript objects. Here is an example of how to do it.
Create an object of name '_temp':
var _temp = {};
When you iterate through 'data' variable then, you can dynamically add attributes to it,say _temp['data0'], _temp['data1'] etc, and every attribute will be an array. For that, you need to write something like:
for(var k=0;k<data.length-1;k++)
{
_temp['data'+k] = data[k].split(',');
}
This will not create the variables identical to what you want. However, this is similar to what you want.
used
window['_temp'+k]= data[k].split(',');
instead of
'_temp'+k= data[k].split(',');
and it worked, thanks to go-oleg

Javascript removing and rearranging array elements

I have this collection of images resources where that is stored in array, the user will select an image and then the selected image will be removed from the list(also from the array) and after that The array would be rearrange. How could I perform such task? (as much as possible I do not want to use an open source library)
Sounds like you need to look up splice() method. It allows you to add and remove one to many items within an array at any index.
here's reference for it.
https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Array/splice
your question lacks a code example but you can use Array.splice(index,number) whereas index is zero based and number is how many items to remove.
images.splice(selectedIndex,1);
Simply, you can create a temporary array where you store the initial array elements you need and reassign the value of your initial array to the temporary array.
function clean_array(my_array){
var no_need_value = 'value you want to remove'
var tmpArray = new Array()
for (var i = 0; i < my_array.length; i++)
if (my_array[i] != no_need_value)
tmpArray.push(my_array[i])
my_array = tmpeArray
}

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