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challenge09.js
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challenge09.js
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////https://adventjs.dev/challenges/09
console.log(groupBy([6.1, 4.2, 6.3], Math.floor)) // { 6: [6.1, 6.3], 4: [4.2] }
console.log(groupBy(['one', 'two', 'three'], 'length')) // { 3: ['one', 'two'], 5: ['three'] }
console.log(groupBy([{ age: 23 }, { age: 24 }], 'age')) // { 23: [{age: 23}], 24: [{age: 24}] }
console.log(
groupBy([1397639141184, 1363223700000], (timestamp) =>
new Date(timestamp).getFullYear()
)
)
// { 2013: [1363223700000], 2014: [1397639141184] }
console.log(
groupBy(
[
{ title: 'JavaScript: The Good Parts', rating: 8 },
{ title: 'Aprendiendo Git', rating: 10 },
{ title: 'Clean Code', rating: 9 },
{ title: 'Clean Code hola', rating: 10 },
],
'rating'
)
)
// { 8: [{ title: 'JavaScript: The Good Parts', rating: 8 }],
// 9: [{ title: 'Clean Code', rating: 9 }],
// 10: [{ title: 'Aprendiendo Git', rating: 10 }] }
export default function groupBy(collection, it) {
// ¡No olvides compartir tu solución en redes!
let output = {}
collection.map((item) => {
let key = typeof it === 'function' ? it(item) : item[it]
output[key] = output[key] ? output[key].concat(item) : [item]
})
return output
}