How can I group JSON Array by multiple Keys in Nodejs.
Is there any solution with underscore or lodash (does not matter if its plain javascript)?
Array:
[{ key: '2017-1', y: 1, gkey: 'y' },
{ key: '2017-1', x: 1, gkey: 'x' }]
Expected Result :
[{ key: '2017-1', x: 1, y:1 }]
You can use reduce and Object.values
let arr = [
{ key: '2017-1', y: 1, gkey: 'y' },
{ key: '2017-1', x: 1, gkey: 'x' },
{ key: '2017-2', x: 1, gkey: 'x' },
];
let result = Object.values(arr.reduce((c, {key,gkey,...r}) => {
c[key] = c[key] || {key};
c[key] = Object.assign(c[key], r);
return c;
}, {}));
console.log(result);If you cant use Object.values on your nodejs version, you can:
let arr = [
{ key: '2017-1', y: 1, gkey: 'y' },
{ key: '2017-1', x: 1, gkey: 'x' },
{ key: '2017-2', x: 1, gkey: 'x' },
];
let temp = arr.reduce((c, {key,gkey,...r}) => {
c[key] = c[key] || {key};
c[key] = Object.assign(c[key], r);
return c;
}, {});
let result = [];
for (let key in temp) result.push(temp[key]);
console.log(result);if I understood correctly what you need, the reduce function could do what you need.
reduce call the function for each element of the array. arr is the result array who will be return by the reduce at the end. I check for each elem if it's in the arr. if not, I add it.
I did not test this code, but it should work
arrayOfData.reduce((arr, elem) => {
let e = arr.find(el => el.key === elem.key);
if(!e) {
e = {key : elem.key}
arr.push(e);
}
e[elem.gkey] = elem[elem.gkey];
return arr;
}, [])
{key:"2017-1", x:1,y:1,t:1}
[{key : '2017-1', x : 1, gkey : 'x'}, {key : '2017-1', y : 1, gkey : 'y'}, {key : '2017-1', t : 1, gkey : 't'}] it give me : {key:"2017-1", x:1,y:1,t:1}
merge.all(r);r is the Array.