get smallest key in array js code example

Example 1: Obtain smallest value from array of objects in Javascript

myArray.sort(function (a, b) {
    return a.Cost - b.Cost
})

var min = myArray[0],
    max = myArray[myArray.length - 1]

Example 2: array with objects read element with the lowest value

myArray.reduce(function(prev, curr) {
    return prev.Cost < curr.Cost ? prev : curr;
});