Question

14

Aggregate an array of objects in JavaScript

rated 0 times [ 21] [ 7] / answers: 1 / hits: 10438 / 5 Years ago, thu, october 17, 2019, 12:00:00

I have an array of objects having a boolean field X. [{..., x: true, y: 3, ...]

I need to aggregate this array, in order to obtain a value, true(or false), if all values of x are correspondingly true(or false), otherwise undefined... and a sum of y's...

is that possible to use the reduce Array function, groupby by underscorejs, or another one for this purpose?

ex:

[

 {a:'titi', x: true,  y: 3}, 

 {a:'toto', x: false, y: 6}

]

result

       {x: undefined, y: 9}

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daren

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answered 5 Years ago kristopherw · Accepted Answer

this is pretty straight-forward with reduce:

.reduce((a, b) => ({

   x: a.x == b.x ? a.x : undefined,

   y: a.y + b.y

}))

Live example:

var input = [

       {a:'titi', x: true,  y: 3}, 

       {a:'toto', x: false, y: 6}

    ];

    

console.log(input.reduce((a, b) => ({

   x: a.x == b.x ? a.x : undefined,

   y: a.y + b.y

})));