Уважаемые знатоки, возможно ли ускорить функцию groupBy хотя бы в 1,5 раза (для node.js)?
/**
* Group items by field
*
* items = [
* {id: 1, name: 'A', val: 1, smth: true},
* {id: 2, name: 'B', val: 2, ...},
* {id: 3, name: 'A', val: 3, ...},
* {id: 4, name: 'B', val: 4, ...},
* {id: 5, name: 'A', val: 5, ...}
* ]
*
* groupBy(items, 'name', ['val', ...]) =
* [
* {
* groupField: 'name',
* groupValue: 'A',
*
* // Items of the group
* items: [{id: 1, name: 'A', val: 1, , smth: true}, {id: 3, name: 'A', val: 3}, {id: 5, name: 'A', val: 5}],
*
* // Values of first item
* id: 1,
* smth: true,
* ...
*
* // Summed values
* val: 9,
* ...
* }, {
* groupField: 'name',
* groupValue: 'B',
* items: [{id: 2, name: 'B', val: 2}, {id: 4, name: 'B', val: 4}],
* id: 2,
* val: 6,
* ...
* }
* ]
*
* @param items - Array<any> - items array
* @param field - string - field name
* @param sumFields - Array<string> - array with names of fields which should be summed
* @returns Array<any>
*/
function groupBy(items, field, sumFields = []) {
const groupsMap = {};
for (let i = 0; i < items.length; i++) {
const item = items[i];
const groupValue = item[field];
let group = groupsMap[groupValue];
if (!group) {
group = {items: [], groupField: field, groupValue: groupValue, ...item};
groupsMap[groupValue] = group;
}
// Add values which should be summed
for (let j = 0; j < sumFields.length; j++) {
const fieldName = sumFields[j];
const sumValue = item[fieldName];
if (sumValue) {
group[fieldName] += sumValue;
}
}
group.items.push(item);
}
return Object.keys(groupsMap).map(key => groupsMap[key]);
}
function generateData(amount) {
return Array.from({length: amount}, (v, i) => {
return {
id: i,
group: String.fromCharCode(Math.floor(Math.random() * 25) + 65),
string: Math.random().toString(36).substring(2),
number: Math.random() * 100,
number2: Math.random() * 1000,
null: null,
undefined: undefined,
boolean: true
}
})
}
const data = generateData(100000)
console.time('Groupping')
grouped = groupBy(data, 'group', ['number', 'number2'])
console.timeEnd('Groupping')
