How to map truthy values to separate objects in js/lodash in an object to array?

Question

How to convert this using lodash/vanilla javascript

const obj = {
'red': {'1': true, '2': false, '3':true},
'green': {'1': false, '2': false, '3':true},
'blue': {'1': true, '2': true, '3':true},
}

to this:

const resultArray = 
[
{'red': '1'}, {'red': '3'},
{'green': '3'},
{'blue': '1'}, {'blue': '2'},
]

Here all the keys whose values are truthy are mapped to 'red', 'green' or 'blue' in array.

Answer 1

So what you want to do is iterate all the object entries (keys => values) and for each of those, filter out the falsy values and map those entries your desired format.

You can then flatten the new array to get the final result you want.

 const obj = { 'red': {'1': true, '2': false, '3':true}, 'green': {'1': false, '2': false, '3':true}, 'blue': {'1': true, '2': true, '3':true}, } const resultArray = Object.entries(obj).map(([ key, vals ]) => Object.entries(vals).filter(([ _, flag ]) => flag).map(([ idx ]) => ({ [key]: idx })) ).flat() console.info(resultArray)

Answer 2

 const obj = { 'red': {'1': true, '2': false, '3':true}, 'green': {'1': false, '2': false, '3':true}, 'blue': {'1': true, '2': true, '3':true}, }; const out = Object.keys(obj).flatMap(color => { return Object.entries(obj[color]).filter(([k, v]) => Boolean(v)).map(([k]) => ({[color]: k})); }); console.log(out);