Answers for "find the lowest number in an array of objects"

javascript array find highest value of array of objects by key

Math.max.apply(Math, array.map(function(o) { return o.y; }))

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]