I've got javascript map with structure like this:
let map = {3 => 1,
15 => 2,
0 => 2,
8 => 3,
9 => 3}
I need to receive the arrays of keys, and keys with similar values should be in the same array.
[[3], [15,0],[8,9]]
This is what I've tried:
let answers = [];
let currentVal = 1;
map.forEach((value, key)=>{
let subArr = [];
if(value === currentVal){
subArr.push(key);
answers.push(subArr);
currentVal++;
}
});
return answers;
And it returns [[3], [15], [8]]
I assume your map is an object, not map for readability reasons, but if u are using Map there you can change methods to get elements but main idea you can see below:
const data = {
3: 1,
15: 2,
0: 2,
8: 3,
9: 3
};
const customData = Object.entries(data).reduce((acc, [key, value]) => {
if (value in acc) {
acc[value].push(key);
} else {
acc[value] = [key];
}
return acc;
}, {});
const finalArray = Object.values(customData);
console.log(finalArray);Edit with Map() example:
const data = new Map([
[3, 1],
[15, 2],
[0, 2],
[8, 3],
[9, 3]
]);
const customData = Array.from(data).reduce((acc, [key, value]) => {
if (value in acc) {
acc[value].push(key);
} else {
acc[value] = [key];
}
return acc;
}, {});
const finalArray = Object.values(customData);
console.log(finalArray);
You could use Object.entries and destructuring key, value but I change their place as value, key to match the data structure map provided by OP :
let map = { 3: 1, 15: 2, 0: 2, 8: 3, 9: 3 };
const arr = [];
for (const [value, key] of Object.entries(map)) {
if (arr[key]) {
arr[key].push(value);
} else {
arr[key] = [value];
}
}
console.log(arr.filter(Boolean)); // [[3], [15,0],[8,9]]NOTE arr.filter(Boolean) to remove falsy (empty) values from array since index 0 have no array inside of it!