Sorting a Map!

gistfile1.txt

Sort by key

Numbers/Dates
new Map([...map].sort((a, b) => a[0] - b[0]))

Strings
new Map([...map].sort((a, b) => +(a[0] > b[0]) || +(a[0] === b[0]) - 1))


Sort by an object property value

Numbers/Dates
new Map([...map].sort((a, b) => a[1][propertyName] - b[1][propertyName]))

Strings
new Map([...map].sort((a, b) => +(a[1][propertyName] > b[1][propertyName]) || +(a[1][propertyName] === b[1][propertyName]) - 1))


[...map]
is shorthand for 
Array.from(map) 
and is the same as 
[...map.entries()]


The string compare function is shorthand for this!

function compare(a, b) {
  if (a < b) {
    return -1;
  }
  if (a > b) {
    return 1;
  }
  // a must be equal to b
  return 0;
}

The + is used to turn true = 1 and false = 0