Get key with minimum value

To get only the minimum number you can use Math.min(...Object.entries(arr).map(o => o[1])):

const arr = {lst1: 300, lst2: 381, lst3: 4, lst4: 4, lst5: 49};
const lowestValue = Math.min(...Object.entries(arr).map(o => o[1]));

console.log(lowestValue);

And to get the object with the minimum value you can use Object.entries(arr).reduce((a, [k, v]) => a[Object.keys(a)[0]] < v ? a : {[k]: v}, {}):

const arr = {lst1: 300, lst2: 381, lst3: 4, lst4: 4, lst5: 49};
const lowestObj = Object.entries(arr).reduce((a, [k, v]) => a[Object.keys(a)[0]] < v ? a : {[k]: v}, {});

console.log(lowestObj);

There are many ways to approach your problem, but here is one simple alternative way to do it. Basically, it is a brute force way of doing things, whereby you iterate through every property to check for the value.

const obj = {lst1: 300, lst2: 381, lst3: 4, lst4: 4, lst5: 49};

const getSmallest = function (object) {
  let smallestValue = Number.MAX_VALUE;
  let selectedKey = '';
  for (let key in object) {
    if (object[key] < smallestValue) {
      smallestValue = object[key];
      selectedKey = key;
    }
  }; 
  console.log(selectedKey, smallestValue)
  return `The lowest value is ${smallestValue} from ${selectedKey}`;
};

getSmallest(obj);

There are several ways to arrive at what you want. Please see the following methods:

const obj = { lst1: 300, lst2: 381, lst3: 4, lst4: 4, lst5: 49 }
const values = Object.values(obj)
const lowest = Math.min.apply(null, values)

// Using Object.keys(), Object.values() and findIndex()
const keys = Object.keys(obj)
const indexOfLowest = values.findIndex(function (x) { return x === lowest })
console.log(`The lowest value is ${lowest} from ${keys[indexOfLowest]}`)



// OR Using Object.keys() and filter()
const key = Object.keys(obj).filter(function (x) { return obj[x] === lowest })[0]
console.log(`The lowest value is ${lowest} from ${key}`)



// OR Using Object.entries() and sort()
const [[lowestKey, lowestVal]] = Object.entries(obj).sort(function ([,valA], [,valB]) { return valA - valB });
console.log(`The lowest value is ${lowestVal} from ${lowestKey}`)

You can get the key and value using Object.entries:

var arr = {
  lst1: 300,
  lst2: 381,
  lst3: 4,
  lst4: 4,
  lst5: 49
};

function lowestValueAndKey(obj) {
  var [lowestItems] = Object.entries(obj).sort(([ ,v1], [ ,v2]) => v1 - v2);
  return `Lowest value is ${lowestItems[1]}, with a key of ${lowestItems[0]}`;
}

var lowest = lowestValueAndKey(arr);
console.log(lowest);

Tags:

Javascript

Arrays

Object

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