How to convert Map keys to array

Question

Lets say I have the following map   let myMap   new Map   set  a   1  set  b   2     And I want to obtain   a    b   based on the above  My current solution seems so long and horrible   let myMap   new Map   set  a   1  set  b   2   let keys       for  let key of myMap    keys push key   console log keys     There must be a better way  no

User · Accepted Answer

Map keys   returns a MapIterator object which can be converted to Array using Array from   let keys   Array from  myMap keys           a    b     EDIT  you can also convert iterable object to array using spread syntax  let keys       myMap keys           a    b

User · Answer

Array from myMap keys    does not work in google application scripts   Trying to use it results in the error TypeError  Cannot find function from in object function Array      native code for Array Array  arity 1      To get a list of keys in GAS do this   var keysList   Object keys myMap

User · Answer

You can use the spread operator to convert Map keys   iterator in an Array    x000D   x000D  let myMap   new Map   set  a   1  set  b   2  set 983  true  x000D  let keys       myMap keys    x000D  console log keys  x000D   x000D   x000D

User · Answer

myMap map   x       gt   x     Above should also work

User · Answer

I need something similiar with angular reactive form   let myMap   new Map   set 0   status   VALID    set 1   status   INVALID     let mapToArray   Array from myMap values     let isValid   mapToArray every x   gt  x status      VALID

User · Answer

OK  let s go a bit more comprehensive and start with what s Map for those who don t know this feature in JavaScript    MDN says      The Map object holds key-value pairs and remembers the original   insertion order of the keys    Any value  both objects and primitive   values  may be used as either a key or a value    As you mentioned  you can easily create an instance of Map using new keyword    In your case   let myMap   new Map   set  a   1  set  b   2     So let s see     The way you mentioned is an OK way to do it  but yes  there are more concise ways to do that     Map has many methods which you can use  like set   which you already used to assign the key values     One of them is keys   which returns all the keys     In your case  it will return   MapIterator   a    b     and you easily convert them to an Array using ES6 ways  like spread operator     const b       myMap keys

User · Answer

Not exactly best answer to question but this trick new Array    someMap  saved me couple of times when I need both key and value to generate needed array  For example when there is need to create react components from Map object based on both key and value values     let map   new Map      map set  1   1     map set  2   2     console log new Array    map  map pairs   gt  pairs 0     - gt    1    2

[javascript] How to convert Map keys to array?

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