Separate objects in an array from their index using localstorage - javascript

I am looking for a way to separate objects from an array, having only the index avaiable. I have something like this:
var hello= [];
for (var i=0; incr.lenght>0; i++;)
{
hello+= originalarray[incr[i]].item;
}
Array:
0: item0
1: item1
2: item2
3: item3
Having this: hello+= originalarray[incr[0,2,3]].item;
I get this: item0item2item3
The "item" comes from another array, this is a small part of my code, but hopefully it's enough to explain my problem.
When I create an alert(hello); what I get is a list of item like this: item0item1item2item3. What I am looking for is a way to separate them. But I need to use the localStorage as well, and I was thinking of creating a different key for every value of the index. Hope it makes sense, I am a new user. Thank you very much!

First of all, the for loop you have in your question has several issues:
It has three ;, while the syntax only allows two. You need to remove the final one
It has a condition that is never true, because lenght has a spelling mistake. If you correct it it will always be true (infinite loop):
incr.length>0
This should be:
i < incr.length
Then the main issue is that you apply a string operator (+=) to concatenate the items, and so hello is no longer an array, but a string:
hello+= originalarray[incr[i]].item;
Instead you should use push:
hello.push(originalarray[incr[i]].item);
In order to store hello in localStorage you should not try to make a key for each item and store each separately. Instead use JSON.stringify (for writing) and JSON.parse (for reading) as explained in this Q&A.

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.

How do you iterate over a JavaScript object's properties like an array?

I don't mean using a for loop using the keys.
For example if you had an array like:
var fruitArray = ["Apples", "Bananas", "Coconuts"],
curFruit = 0;
You could "iterate" over that using buttons, say you've got a prev/next button and all those buttons do is decrement/increment the curFruit index.
So if I'm on Bananas, I could get Apples using the prev button using:
fruitArray[0] // Apples
Where the index was at 1 for Bananas but the prev button drops the index by one.
So with an unknown-length object, and not using a numbered-index, how could you do that?
Say it's like this:
var fruitObject = {"Apples":"Red", "Bananas":"Yellow", "Coconuts":"Brown"};
I realize you could have set 0, 1, 2 and the fruit name, but just to show that you don't know what the object key/index might be.
So if I'm on Bananas using
fruitObject.Bananas // yellow
How could I get to Apples using the same decrement idea as the Array?
My question is not about the for in method
I don't know why that's not clear, it was literally the first line in my question.
I think I found a solution anyway though it might not be direct/the most effective way to do it where I'll create a temporary local "look up".
To explain:
Here's an object
var colorObject = {"red":"apple", "blue":"blueberries", "yellow":"banana"};
I don't want to use the for in method to go from left to right complete.
I want to be able to start/keep a current position like I'm at "blue":"berries" and I can jump to "red":"apple" without knowing what "red":"apple" is
My current solution in mind is, yes, though ironically I would use the for in method but to create a look up array.
Something like
var tempArray = [];
for (var key in colorObject) {
tempArray.push(key);
}
Then I can navigate the object starting from anywhere using the increment/decrement method.
tempArray[1] would return "blue" and I could go to "red" by doing tempArray[0] which is interpreted as
colorObject.blue // blueberries
Edit thanks to the editor for making my question more clear
I did poorly word it so that's on me.
This is not possible. JavaScript object properties do not have a defined order, so there is no concept of Y key comes after X key.
Excerpt from EnumerateObjectProperties section of ECMAScript 2017 Draft (ECMA-262) (emphasis added):
The mechanics and order of enumerating the properties is not specified but must conform to the rules specified below.
If you were to iterate over the properties of your fruitObject object, "Bananas" may or may not come before "Coconuts", this behavior simply is not defined by the specification. There does not even appear to be a guarantee the properties will come back in the same order each time you iterate over the properties.
The only way to have a consistent order would be to have an array. Optionally, you could do this by creating an array of the properties via Object.keys.
var fruitObject = {"Apples":"Red", "Bananas":"Yellow", "Coconuts":"Brown"};
// Get the property keys in an ordered list:
var fruitObjectKeys = Object.keys(fruitObject);
// An array of properties with a consistent order:
fruitObjectKeys.forEach(function(prop) {
console.log(prop, '=', fruitObject[prop]);
});
Note however that the JavaScript engine running the code will decide what the order of the resulting array of properties is if you do it this way.
Objects don't have order, so you can't say that the first element of fruitObject is "Apples", the second is "Bananas" and the third is "Cocounts".
You could get the keys as an array with Object.keys() and then do something like
var keys=Object.keys(fruitObject);
fruitObject[keys[0]];
Remember that in JS it's the obj.key is the same than obj["key"].

How to compare two objects

I have a scenario, where I have two different Objects.
Scenario to achieve:
From two objects I need to match the values which has "A1","B2", etc...
Since both the objects values are not in proper order, the loop is breaking and missing some values.
In my demo the object1 has same repeated value i.e. "C3", It should be displayed only once.
Final output required is I need to detect only the matched values from two objects and display its corresponding "a" and "b values."
I have tried almost 90%, but somewhere some minor error is breaking my loop, Please help me out.
Sample code:
for(var i=0;i<obj1.results[0].loc.length;i++){
var findA = obj1.results[0].loc[i].anc[0].title;
for(var j=0;j< obj2.ILoc.length;j++){
var findB = obj2.ILoc[j].ais;
if(findA == findB) {
var a = obj1.results[0].loc[i].a;
var b = obj1.results[0].loc[i].b;
console.log(a);
console.log(b);
}
}
}
This is what I have tried:
Demo Link
I would recommend using for...in loop, since you're using objects instead of arrays.
for (variable in object) {...
}
If length property of both objects is equal, then this kind of loop alone will help you to compare objects with ease.
I would recommend using the diff module. You can use it in node.js and the browser.

What data structure or iterative methods to be used to get circular list behavior in javascript

Say I have a collection [1,2,3,4] I would like to iterate from 1st element to last element and then back to first element. so it should be 1,2,3,4,1,2,3,4,1,2.... till some thing is true.
currently I am thinking of
while(IsSomethingTrue)
{
for(var i=0;i<Myarr.length;i++)
{
//do-something
if(i==(Myarr.length-1))
{
i=0; //setting it back to first index
}
}
}
I know this is a elementary question and above is one way I could achieve the goal but was wondering is there any better way like a data structure along the lines of circular list or any looping methods in javascript that could go on iterating till the end of array and start from beginning again.
For those why i need this is: I am trying to visualize Dining philosophers in Javascript and need this kind of a behavior to happen.
While the performance will be decreased, if you just wanted shorter code, and if you don't mind mutating the Array, you could do this:
while(IsSomethingTrue)
{
var item = Myarr[0];
// do something with item
Myarr.push(Myarr.shift());
}
Again, to be clear, there will most certainly be some performance impact. Just thought I'd show it as a possibility.
You could also shallow clone the Array using .slice() before entering the while loop if you don't want to mutate the original.
The solution you stated is efficient and readable enough. A single if-statement is not very costly.
Another solution is to use a circular linked list. But I don't think that would gain you anything unless you will be inserting elements into the data structure.
Your logic is fine, but you can save a few characters-
var a= Myarr, L= a.length, i= 0;
while(i<L){
//do-something with a[i]
if(++i== L) i= 0; // increment or reset
}

Joining values in an Javascript array

Say I have:
var Certificated = {}
Sub items are added dynamically and variate. Possible outcome:
var Certificated = {
Elementary: ["foo","bar", "ball"]
MiddleSchool: ["bar", "crampapydime"]
};
I want to do the following:
Certificated.Elementary = Certificated.Elementary.join("");
Except I need it to do that on all of the objects inside.
Keep in mind I can't know for sure the titles of nor how many objects will be inside Certificated.
My question is how can I use .join("") on all elements inside Certificated, without calling each one specifically?
EDIT: I am aware .join() is for arrays and the objects inside Certificated are going to be arrays. Therefore the join method.
Does this work?
for (var key in Certificated) {
if (Certificated.hasOwnProperty(key)) {
Certificated[key] = Certificated[key].join("");
}
}
It loops through all properties of Certificated, and makes a quick safe check for the key being a real property, then uses bracket notation - [""] - to do your join.
Quick question - are you sure you want to use join? I know you just provided an example, but you can't call join on a string...it's for arrays. Just wanted to make sure you knew.
Here's a jsFiddle of my code working with arrays being used for the properties:
http://jsfiddle.net/v48dL/
Notice in the browser console, the properties' values are strings because the join combined them with "".

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