Is it possible to convert
[[35, "Bill"], [20, "Nancy"], [27, "Joan"]]
to
{"Bill": 35, "Nancy": 20, "Joan": 27}
using the .map() or .reduce() methods?
I can convert the array using:
const arr = [[35, "Bill"], [20, "Nancy"], [27, "Joan"]];
let obj = {};
for (let item of arr) {
obj[item[1]] = item[0];
}
console.log(obj);But my attempts to do this using map or reduce are failing. Any ideas?
If supported, you can use Object.fromEntries() to convert an array of [key, value] pairs to an object. In this case, the pairs are [value, key], so we'll need to map them first to an array of [key, value] pairs.
const arr = [[35, "Bill"], [20, "Nancy"], [27, "Joan"]];
const obj = Object.fromEntries(arr.map(([v, k]) => [k, v]));
console.log(obj);Use Array.map() to create an array of objects where each contains a single key/value. Combine them to a single object by spreading into Object.assign():
const arr = [[35, "Bill"], [20, "Nancy"], [27, "Joan"]];
const obj = Object.assign(...arr.map(([v, k]) => ({ [k]: v })));
console.log(obj);If you need to use the object as a dictionary, a better solution would be to convert the array of tuples to a Map:
const arr = [[35, "Bill"], [20, "Nancy"], [27, "Joan"]];
const map = new Map(arr.map(([v, k]) => [k, v]));
console.log(map.get('Bill'));
[k]) in the map return? I was doing something similar but had ...=> ({k: v}) without the brackets.
k. To get the value, you need to use computed property names - [k].Yes, you can use reduce - on each iteration, extract both items from the array (as the key and the value), assign the value to the appropriate key in the accumulator, and return the accumulator:
const input = [[35, "Bill"], [20, "Nancy"], [27, "Joan"]];
const obj = input.reduce((a, [val, key]) => {
a[key] = val;
return a;
}, {});
console.log(obj);
You could map the items for new objects and assign all to a single object with Object.assign.
var array = [[35, "Bill"], [20, "Nancy"], [27, "Joan"]],
object = Object.assign(...array.map(([v, k]) => ({ [k]: v })));
console.log(object);You can use reduce with Object.assign:
let array = [[35, "Bill"], [20, "Nancy"], [27, "Joan"]];
let result = array.reduce((acc, [value, key]) => Object.assign(acc, { [key]: value }), {});
console.log(result);
