I have 3 different test cases, each of which is passed to the function getEarliest below:
{}
{ '2022-04-29': 1 }
{ '2022-04-29': 3, '2022-04-30': 2, '2022-04-28': 3, '2022-05-02': 2 }
From each test case, I want to return the key:value with the smallest date and the biggest value. My problem is at the third test case, I'm getting '2022-04-29': 3 instead of '2022-04-28': 3
getEarliest = dates => {
return Object.keys(dates).reduce((prev, curr) => {
if (dates[curr] > prev.date) {
return {
val: dates[curr],
date: curr
};
} else {
return prev;
}
}, {
val: 0,
date: null
}); }
expected result test case 1 : { val: 0, date: null }
expected result test case 2 : { val: 1, date: '2022-04-29' }
expected result test case 3 : { val: 3, date: '2022-04-28' }
Looks like you need just sort object by two parametrs:
const test1 = {};
const test2 = { '2022-04-29': 1 };
const test3 = { '2022-04-29': 3, '2022-04-30': 2, '2022-04-28': 3, '2022-05-02': 2 };
const test4 = { '2022-04-29': 4, '2022-04-28': 4, '2022-04-30': 4, '2022-05-02': 2 };
const getEarliest = (dates) => {
const [date, val] = Object.entries(dates)
.sort(([k1, v1], [k2, v2]) => v2 - v1 || Date.parse(k1) - Date.parse(k2) )
.at(0) ?? [null, 0];
return { val, date };
};
console.log(getEarliest(test1));
console.log(getEarliest(test2));
console.log(getEarliest(test3));
console.log(getEarliest(test4));.as-console-wrapper {max-height: 100% !important; top: 0}And the same result with reduce:
const test1 = {};
const test2 = { '2022-04-29': 1 };
const test3 = { '2022-04-29': 3, '2022-04-30': 2, '2022-04-28': 3, '2022-05-02': 2 };
const test4 = { '2022-04-29': 4, '2022-04-28': 4, '2022-04-30': 4, '2022-05-02': 2 };
const getEarliest = (dates) => {
const [date, val] = Object.entries(dates)
.reduce((prev, curr) => (curr[1] - prev[1] || Date.parse(prev[0]) - Date.parse(curr[0])) > 0
? curr
: prev
, [null, 0]);
return { val, date };
};
console.log(getEarliest(test1));
console.log(getEarliest(test2));
console.log(getEarliest(test3));
console.log(getEarliest(test4));.as-console-wrapper {max-height: 100%!important;top:0 }In your code prev.date value is initially null. so reduce() will always return the initial object.
Try this code it's help you
getEarliest = (dates) => {
if (Object.keys(dates).length > 0) {
let date = Object.keys(dates).reduce((prev, curr) => {
if (prev > curr) {
return curr;
} else {
return prev;
}
});
return {
val: dates[date],
date: date
}
} else {
return {
val: 0, date: null
}
}
}
Because you have 2 sort conditions so they have to be put in a certain order. From your examples I assume that order is: "biggest value" -> "smallest date". Then your if will become like below:
getEarliest = (dates) => {
return Object.keys(dates).reduce(
(prev, curr) => {
if (dates[curr] > prev.val || (dates[curr] === prev.val && curr < prev.date)) {
return {
val: dates[curr],
date: curr,
}
} else {
return prev
}
},
{
val: 0,
date: null,
}
)
}