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javascriptloopsfilterindexof
Kevin
Kevin

Reputation: 335

Filter foreach index value in Javascript

How to filter index value in foreach Javascript with condition if

last_login = null

then store the filtered values to

this.searchLogin

Image below is the ouput of: console.log(obj);

enter image description here

Here' what I've done so far:

try {
   this.searchTrigger = true
   var obj = this.list;

   this.searchLogin = [];

   for (let i=0; i < obj.length; ++i){
       if(obj.filter( x => obj[i].profile.last_login === null)){
          this.searchLogin.push(obj[i]);
       }
   }

console.log('This are obj data passed to search login',this.searchLogin);

Upvotes: 1

Views: 820

Answers (3)

Ziv Ben-Or
Ziv Ben-Or

Reputation: 1194

var obj = [
{ profile: { last_login: null } },
{ profile: { last_login: true } },
{ profile: { last_login: null } },
{ profile: { last_login: true } },
{ profile: { last_login: null } }]



//With filter and map
console.log("With filter and map: ", 
        obj.map((x, i) => ({ ...x.profile, i }))
            .filter(x => !x.last_login)
            .map(x => x.i));



//With reduce
console.log("With reduce: ",
        obj.reduce((p, c, i) => (!c.profile.last_login && p.push(i), p), [])
        )

Upvotes: 1

Nikhil Aggarwal
Nikhil Aggarwal

Reputation: 28475

There are some points that need to be noted

  • filter function will return an array and even if it empty (no matched results), it will still be evaluated as true i.e. your if condition will always be executed
  • The if condition has a filter function inside a for loop which means that you are unnecessarily checking condition for same object for all the objects in array i.e. for each object the filter function will either return empty array or array of all the objects.

You can use Array.reduce and store the last_login information in the resultant array

this.searchLogin = this.list.reduce((a,c) => c.profile.last_login === null ? a.concat(c.profile.last_login) : a, []);

Upvotes: 0

Sasi Kumar M
Sasi Kumar M

Reputation: 2630

I think no need to save the results explicitly to an array again, the filter on array by itself will create an results array based on the filter condition.

For more on filter,

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter

In your case,

 this.searchLogin = obj.filter( x => x.profile.last_login === null);

would do the trick.

Upvotes: 0

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