React native for loop getting index

Question

This is probably a super simple question, but I have the following:

let groups = [{}, {}, {}];

for(let g of groups) {
    console.log(g);
}

How do I get the index number of said group? Preferably without doing a count.

I'm not sure about React, but in javascript there is ```for-in``` that goes through indices — Stefan Octavian, Apr 01 '18 at 17:37

score 5 · Answer 1 · answered Apr 01 '18 at 17:37

5

Alternatively use forEach():

groups.forEach((element, index) => {
    // do what you want
});

answered Apr 01 '18 at 17:37

Code-Apprentice

I get `.forEach() is not a function` – bryan Apr 01 '18 at 17:48
@bryan Do you have the same definition of `groups` as in your question? – Code-Apprentice Apr 01 '18 at 18:51

score 3 · Accepted Answer · answered Apr 01 '18 at 17:37

Instead of looping through groups, you could loop through groups.entries() which returns for each element, the index and the value.

Then you can extract those value with destructuring:

let groups = [{}, {}, {}];

for(let [i, g] of groups.entries()) {
    console.log(g);
}

score 2 · Answer 3 · answered Apr 01 '18 at 17:36

2

Simply,

let groups = [{}, {}, {}];

for(let g of groups) {
    console.log(groups.indexOf(g));
}

answered Apr 01 '18 at 17:36

Matus Dubrava

3 Answers3