Category Theory - Monoid Strings and Arrays

category-theory-monoid-strings-and-arrays.ts

String.prototype.mappend = function (x: String): String {
    return this + x
}

String.prototype.mempty = function (): String {
    return ""
}

console.log(
    'String mappend:',
    String("category").mappend(" ").mappend("theory")
) // "category theory"
console.log('String mempty:', String().mempty()) // ""


Array.prototype.mappend = function (x: Array): Array {
    return this.concat(x)
}

Array.prototype.mempty = function (): Array {
    return []
}

console.log('Array mappend:', Array(1, 2).mappend([3])) // [1, 2, 3]
console.log('Array mempty:', Array().mempty()) // []