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Group values on same property - JavaScript
Suppose we have an array like this −
const arr = [
{unit: 35, brand: 'CENTURY'},
{unit: 35, brand: 'BADGER'},
{unit: 25, brand: 'CENTURY'},
{unit: 15, brand: 'CENTURY'},
{unit: 25, brand: 'XEGAR'}
];We are required to write a function that groups all the brand properties of objects whose unit property is the same.
Like for the above array, the new array should be −
const output = [
{unit: 35, brand: 'CENTURY, BADGER'},
{unit: 25, brand: 'CENTURY, XEGAR'},
{unit: 15, brand: 'CENTURY'}
];We will loop over the array, search for the object with unit value using a helper function. If it exists, we concatenate the brand value otherwise we create a new object.
Example
Following is the code −
const arr = [
{unit: 35, brand: 'CENTURY'},
{unit: 35, brand: 'BADGER'},
{unit: 25, brand: 'CENTURY'},
{unit: 15, brand: 'CENTURY'},
{unit: 25, brand: 'XEGAR'}
];
const indexOf = function(unit){
return this.findIndex(el => el.unit === unit)
};
Array.prototype.indexOf = indexOf;
const groupArray = arr => {
const res = [];
for(let i = 0; i < arr.length; i++){
const ind = res.indexOf(arr[i].unit);
if(ind !== -1){
res[ind].brand += `, ${arr[i].brand}`;
}else{
res.push(arr[i]);
}
};
return res;
};
console.log(groupArray(arr));Output
This will produce the following output in console −
[
{ unit: 35, brand: 'CENTURY, BADGER' },
{ unit: 25, brand: 'CENTURY, XEGAR' },
{ unit: 15, brand: 'CENTURY' }
]
Updated on: 18-Sep-2020
233 Views
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