Below is the current data
const data = [
{ id: 1, type: "call", strike: 3000, volume: 50000 },
{ id: 2, type: "call", strike: 5000, volume: 30000 },
{ id: 3, type: "call", strike: 7000, volume: 20000 },
{ id: 4, type: "put", strike: 3000, volume: 50000 },
{ id: 5, type: "put", strike: 5000, volume: 10000 },
{ id: 6, type: "put", strike: 7000, volume: 7000 }
]
I want to do some processing of the data based on strike, which means the object with same value in strike will be combined, so that it becomes something like
[
{ strike: 3000, callVolume: 50000, putVolume: 50000 },
{ strike: 5000, callVolume: 30000, putVolume: 10000 },
{ strike: 7000, callVolume: 20000, putVolume: 7000 },
]
How should I do it in javascript?
This is really just a 'group by' by strike with a computed property name based on type.
const data = [ { id: 1, type: 'call', strike: 3000, volume: 50000 }, { id: 2, type: 'call', strike: 5000, volume: 30000 }, { id: 3, type: 'call', strike: 7000, volume: 20000 }, { id: 4, type: 'put', strike: 3000, volume: 50000 }, { id: 5, type: 'put', strike: 5000, volume: 10000 }, { id: 6, type: 'put', strike: 7000, volume: 7000 }, ];
const result = Object.values(
data.reduce((a, { type, strike, volume }) => {
(a[strike] ??= { strike })[`${type}Volume`] = volume;
return a;
}, {})
);
console.log(result);You could collect volume by each group.
const
data = [{ id: 1, type: "call", strike: 3000, volume: 50000 }, { id: 2, type: "call", strike: 5000, volume: 30000 }, { id: 3, type: "call", strike: 7000, volume: 20000 }, { id: 4, type: "put", strike: 3000, volume: 50000 }, { id: 5, type: "put", strike: 5000, volume: 10000 }, { id: 6, type: "put", strike: 7000, volume: 7000 }],
result = Object.values(data.reduce((r, { type, strike, volume }) => {
r[strike] ??= { strike, callVolume: 0, putVolume: 0 };
r[strike][type + 'Volume'] += volume;
return r;
}, {}));
console.log(result);.as-console-wrapper { max-height: 100% !important; top: 0; }You can use a forEach/for loop to init a item in result object. By using Array.find use can check the result exists or not to init a new result item.
const data = [
{ id: 1, type: "call", strike: 3000, volume: 50000 },
{ id: 2, type: "call", strike: 5000, volume: 30000 },
{ id: 3, type: "call", strike: 7000, volume: 20000 },
{ id: 4, type: "put", strike: 3000, volume: 50000 },
{ id: 5, type: "put", strike: 5000, volume: 10000 },
{ id: 6, type: "put", strike: 7000, volume: 7000 }
]
let result = [];
data.forEach(item => {
let result_item = result.find(e => e.strike == item.strike);
var isNew = false;
if (!result_item) {
result_item = {
strike: item.strike
};
isNew = true;
}
if (item.type == "call")
result_item.callVolume = item.volume;
else
result_item.putVolume = item.volume;
if (isNew) result.push(result_item);
});
console.log(result);