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Grouping nested array in JavaScript
Suppose, we have an array of values like this −
const arr = [
{
value1:[1,2],
value2:[{type:'A'}, {type:'B'}]
},
{
value1:[3,5],
value2:[{type:'B'}, {type:'B'}]
}
];We are required to write a JavaScript function that takes in one such array. Our function should then prepare an array where the data is grouped according to the "type" property of the objects.
Therefore, for the above array, the output should look like −
const output = [
{type:'A', value: [1,2]},
{type:'B', value: [3,5]}
];Example
The code for this will be −
const arr = [
{
value1:[1,2],
value2:[{type:'A'}, {type:'B'}]
},
{
value1:[3,5],
value2:[{type:'B'}, {type:'B'}]
}
];
const groupValues = (arr = []) => {
const res = [];
arr.forEach((el, ind) => {
const thisObj = this;
el.value2.forEach(element => {
if (!thisObj[element.type]) {
thisObj[element.type] = {
type: element.type,
value: []
}
res.push(thisObj[element.type]);
};
if (!thisObj[ind + '|' + element.type]) {
thisObj[element.type].value =
thisObj[element.type].value.concat(el.value1);
thisObj[ind + '|' + element.type] = true;
};
});
}, {})
return res;
};
console.log(groupValues(arr));Output
And the output in the console will be −
[
{ type: 'A', value: [ 1, 2 ] },
{ type: 'B', value: [ 1, 2, 3, 5 ] }
]
Updated on: 23-Nov-2020
559 Views
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