How to iterate keys values in JavaScript

Question

I have a dictionary that has the format of     dictionary    0   object   1  object   2  object    How can I iterate through this dictionary by doing something like     for  key value  in dictionary           Do stuff where key would be 0 and value would be the object

User · Answer

You can do something like this    dictionary     ab    object    cd   object    ef   object   var keys   Object keys dictionary    for var i   0  i  lt  keys length i          keys i  for key      dictionary keys i   for the value

User · Answer

Try this   dict    0  1  a    1  2  b    2  3  c    for  var key in dict     console log  key  dict key        0 Object   1  a   1 Object   2  b   2 Object   3  c

User · Answer

tl dr   In ECMAScript 5  it is not possible  In ECMAScript 2015  it is possible with Maps  In ECMAScript 2017  it would be readily available    ECMAScript 5   No  its not possible with objects   You should either iterate with for  in  or Object keys  like this  for  var key in dictionary           check if the property key is defined in the object itself  not in parent     if  dictionary hasOwnProperty key                        console log key  dictionary key              Note  The if condition above is necessary  only if you want to iterate the properties which are dictionary object s very own  Because for  in will iterate through all the inherited enumerable properties   Or  Object keys dictionary  forEach function key        console log key  dictionary key            ECMAScript 2015  In ECMAScript 2015  you can use Map objects and iterate them with Map prototype entries  Quoting example from that page   var myMap   new Map    myMap set  0    foo    myMap set 1   bar    myMap set      baz     var mapIter   myMap entries     console log mapIter next   value        0    foo   console log mapIter next   value       1   bar   console log mapIter next   value       Object   baz     Or iterate with for  of  like this   use strict    var myMap   new Map    myMap set  0    foo    myMap set 1   bar    myMap set      baz     for  const entry of myMap entries        console log entry       Output     0    foo      1   bar           baz      Or  for  const  key  value  of myMap entries        console log key  value       Output  0 foo 1 bar    baz     ECMAScript 2017  ECMAScript 2017 would introduce a new function Object entries  You can use this to iterate the object as you wanted    use strict    const object     a   1   b   2   c    3   for  const  key  value  of Object entries object       console log key  value       Output  a 1 b 2 c 3

User · Answer

Try this   var value  for  var key in dictionary        value   dictionary key          your code here

User · Answer

You can use JavaScript forEach Loop  myMap forEach  value  key    gt        console log  value     value       console log  key     key

User · Answer

I think the fast and easy way is  Object entries event  forEach k   gt        console log  properties        k 0   k 1          just check the documentation https   developer mozilla org en-US docs Web JavaScript Reference Global Objects Object entries

User · Answer

using swagger-ui js  you can do this -     forEach    a   1   b   2    function n  key        console log n  key

User · Answer

WELCOME TO 2020  Drools in ES6  Theres some pretty old answers in here - take advantage of destructuring  In my opinion this is without a doubt the nicest  very readable  way to iterate an object   x000D   x000D  const myObject         nick   cage       phil   murray       Object entries myObject  forEach   k v     gt        console log  The key    k      console log  The value    v     x000D   x000D   x000D   Edit  As mentioned by Lazerbeak  map allows you to cycle an object and use the key and value to make an array   x000D   x000D  const myObject         nick   cage       phil   murray       const myArray   Object entries myObject  map   k  v     gt        return  The key    k   has a value of    v          console log myArray   x000D   x000D   x000D

User · Answer

The Object entries   method has been specified in ES2017  and is supported in all modern browsers    for  const   key  value   of Object entries dictionary            do something with  key  and  value      Explanation    Object entries   takes an object like   a  1  b  2  c  3   and turns it into an array of key-value pairs       a   1       b   2       c   3      With for     of we can loop over the entries of the so created array  Since we are guaranteed that each of the so iterated array items is itself a two-entry array  we can use destructuring to directly assign variables key and value to its first and second item

User · Answer

As an improvement to the accepted answer  in order to reduce nesting  you could do this instead  provided that the key is not inherited   for  var key in dictionary        if   dictionary hasOwnProperty key             continue            console log key  dictionary key        Edit  info about Object hasOwnProperty here

User · Answer

You can use below script    var obj  1  a  2  b  c  3    for  var x Object keys obj  i 0 i lt x length key x i  value obj key  i         console log key value       outputs 1 a 2 b c 3

[javascript] How to iterate (keys, values) in JavaScript?

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