returns

string | number | boolean

example

import {N} from 'ts-toolbelt'

type test0 = N.Negate<'-10'>     //  '10'
type test1 = N.Negate<'10'>      // '-10'
type test2 = N.Negate<'10', 's'> // '-10'
type test3 = N.Negate<'10', 'n'> //  -10
type test4 = N.Negate<'-100'>    // string