Dynamically create object from object array

Question

I have an array of objects that I need to turn into a new single object.

This is structure of array:

class QueryFilter {
    filterName;
    filterValue;
}

let filter1 = new QueryFilter();
filter1.filterName = "SpamScore";
filter1.filterValue = 5;

let filter2 = new QueryFilter();
filter2.filterName = "Pages";
filter2.filterValue = 50;

let filters = [filter1, filter2];

I need to turn filters into an object like this:

let newObj = {
    SpamScore: 5,
    Pages: 50
};

I have been trying with map and assign but I cant figure out the way I am supposed to do this. Does this require reflection of some type or is there a simple way?

I tried using assign and map and it didn't work so I don't see point of posting it as I am not sure if it is even those methods that I should be using. — Guerrilla
– Guerrilla, Commented Jul 13, 2018 at 4:52
for(let filter of filters) { newObj[filter.filterName] = filter.filterValue } — Tibrogargan
– Tibrogargan, Commented Jul 13, 2018 at 5:20
more fully: let newObj = {}; for(let f of filters) { newObj[f.filterName] = f.filterValue } — Tibrogargan
– Tibrogargan, Commented Jul 13, 2018 at 5:28

31piy · Accepted Answer · 2018-07-13 04:53:54Z

1

You can do it using Array#reduce:

filters.reduce((r, i) => {
  r[i.filterName] = i.filterValue;
  return r;
}, {});

The idea is to loop over the filters object, and in each iteration, assign the key-value to the result.

answered Jul 13, 2018 at 4:53

31piy

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CertainPerformance · Accepted Answer · 2018-07-13 04:55:02Z

1

A simple reduce into an object would do it:

class QueryFilter {
}

let filter1 = new QueryFilter();
filter1.filterName = "SpamScore";
filter1.filterValue = 5;

let filter2 = new QueryFilter();
filter2.filterName = "Pages";
filter2.filterValue = 50;

let filters = [filter1, filter2];

console.log(
  filters.reduce((a, { filterName, filterValue }) => (
    Object.assign(a, { [filterName]: filterValue })
  ), {})
);

answered Jul 13, 2018 at 4:55

CertainPerformance

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1 Comment

Guerrilla Over a year ago

Ahh thanks. Funnily that method didn't come up when i was googling, thank you very much i will accept when timer allows

Isaac · Accepted Answer · 2018-07-13 05:57:11Z

0

let newObj = {}
    
filters.forEach(x=> {
  newObj[x.filterName] = x.filterValue;
})

console.log(newObj)

Alternatively you can also use Array#forEach to achieve what you want

answered Jul 13, 2018 at 5:57

Isaac

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