Declaring array of objects

Question

I have a variable which is an array and I want every element of the array to act as an object by default  To achieve this  I can do something like this in my code   var sample   new Array    sample 0    new Object    sample 1    new Object      This works fine  but I don t want to mention any index number  I want all elements of my array to be an object  How do I declare or initialize it   var sample   new Array    sample     new Object      I tried the above code but it doesn t work  How do I initialize an array of objects without using an index number

User · Answer

Use array push   to add an item to the end of the array   var sample   new Array    sample push new Object       To do this n times use a for loop   var n   100  var sample   new Array    for  var i   0  i  lt  n  i        sample push new Object         Note that you can also substitute new Array   with    and new Object   with    so it becomes   var n   100  var sample       for  var i   0  i  lt  n  i        sample push

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Using forEach we can store data in case we have already data we want to do some business login on data    var sample   new Array    var x   10  var sample    1 2 3 4 5 6 7 8 9   var data        sample forEach function item       data push item       document write data     Example by using simple for loop   var data       for var i   0   i  lt  10   i        data push i     document write data

User · Answer

Well array length should do the trick or not  something like  i mean you don t need to know the index range if you just read it    var arrayContainingObjects       for  var i   0  i  lt  arrayContainingYourItems length  i         arrayContainingObjects push   property  arrayContainingYourItems i         Maybe i didn t understand your Question correctly  but you should be able to get the length of your Array this way and transforming them into objects  Daniel kind of gave the same answer to be honest  You could just save your array-length in to his variable and it would be done   IF and this should not happen in my opinion you can t get your Array-length  As you said w o getting the index number you could do it like this   var arrayContainingObjects       for           try          arrayContainingObjects push   property  arrayContainingYourItems i             catch err       break      It is the not-nice version of the one above but the loop would execute until you  run  out of the index range

User · Answer

Depending on what you mean by declaring  you can try using object literals in an array literal   var sample                              EDIT  If your goal is an array whose undefined items are empty object literals by default  you can write a small utility function   function getDefaultObjectAt array  index        return array index    array index             Then use it like this   var sample       var obj   getDefaultObjectAt sample  0             returned and stored at index 0    Or even   getDefaultObjectAt sample  1  prop    val         prop   val    stored at index 1    Of course  direct assignment to the return value of getDefaultObjectAt   will not work  so you cannot write   getDefaultObjectAt sample  2      prop   val

User · Answer

The below code from my project maybe it good for you    reCalculateDetailSummary updateMode  boolean         var summaryList  any           var list  any      if  updateMode    list   this state pageParams data chargeDefinitionList       else           list   this state chargeDefinitionList             list forEach  item  any    gt            if  summaryList    null    summaryList length    0                var obj                     chargeClassification  item classfication                  totalChargeAmount  item chargeAmount                            summaryList push obj              else               if  summaryList find  x  any    gt  x chargeClassification    item classfication                     summaryList find  x  any    gt  x chargeClassification    item classfication                       totalChargeAmount    item chargeAmount                                       if  summaryList    null  amp  amp  summaryList length    0            summaryList push               chargeClassification   Total               totalChargeAmount  summaryList reduce  a  any  b  any    gt  a   b  totalChargeAmount                       this setState   detailSummaryList  summaryList

User · Answer

const sample           list forEach element   gt          const item      as   name  string  description  string          item name  element name        item description  element description        sample push item               return sample    Anyone try this   and suggest something

User · Answer

You can instantiate an array of  object type  in one line like this  just replace new Object   with your object    var elements   1000  var MyArray   Array apply null  Array elements   map function      return new Object

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making array of book object var books           var new book    id   book1   name   twilight   category   Movies   price  10       books push new book       new book    id   book2   name   The call   category   Movies   price  17       books push new book       console log books 0  id       console log books 0  name       console log books 0  category       console log books 0  price       also we have array of albums var albums              var new album    id   album1   name   Ahla w Ahla   category   Music   price  15       albums push new album       new album    id   album2   name   El-leila   category   Music   price  29       albums push new album     Now  content  0  contains all books  amp  content 1  contains all albums var content       content push books   content push albums   var my books   content 0   var my albums   content 1   console log my books 0  name   console log my books 1  name     console log my albums 0  name   console log my albums 1  name      This Example Works with me  Snapshot for the Output on Browser Console

User · Answer

var ArrayofObjects           An empty array of objects

User · Answer

Use array push   to add an item to the end of the array   var sample   new Array    sample push new Object       you can use it  var x   100  var sample       for let i 0  i lt x  i       sample push        OR   sample push new Object

User · Answer

If you want all elements inside an array to be objects  you can use of JavaScript Proxy to apply a validation on objects before you insert them in an array  It s quite simple   const arr   new Proxy new Array        set target  key  value        if   value     null  amp  amp  typeof value      object      key      length           return Reflect set    arguments         else         throw new Error  Only objects are allowed                    Now if you try to do something like this   arr 0     Hello World      Error   It will throw an error  However if you insert an object  it will be allowed   arr 0           Allowed   For more details on Proxies please refer to this link  https   developer mozilla org en-US docs Web JavaScript Reference Global Objects Proxy  If you are looking for a polyfill implementation you can checkout this link  https   github com GoogleChrome proxy-polyfill

User · Answer

You can use fill      let arr   new Array 5  fill  lol     let arr2   new Array 5  fill   test   a         or if you want different objects let arr3   new Array 5  fill   map     i    gt     id  i        Will create an array of 5 items  Then you can use forEach for example   arr forEach str   gt  console log str      Note that when doing new Array 5  it s just an object with length 5 and the array is empty  When you use fill   you fill each individual spot with whatever you want

User · Answer

Try this-  var arr       arr push

User · Answer

After seeing how you responded in the comments  It seems like it would be best to use push as others have suggested  This way you don t need to know the indices  but you can still add to the array   var arr       function funcInJsFile            Do Stuff     var obj    x  54  y  10       arr push obj       In this case  every time you use that function  it will push a new object into the array

User · Answer

You don t really need to create blank Objects ever  You can t do anything with them  Just add your working objects to the sample as needed   Use push as Daniel Imms suggested  and use literals as Fr  d  ric Hamidi suggested   You seem to want to program Javascript like C   var samples          If you have no data to put in yet        Later  probably in a callback method with computed data       replacing the constants     samples push new Sample 1  2  3       Assuming Sample is an object        or    samples push  id  23  chemical   NO2   ppm  1 4       Object literal       I believe using new Array 10  creates an array with 10 undefined elements

[javascript] Declaring array of objects

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