functional programming functors example

fp-functors.ts

const Id = <T extends {}>(v: T) => {
    return {
        valueOf: () => v,
        map: (fn:any) => Id(fn(v))
    }
};

console.log(
    Id('foo')
        .map(
            (v) => v.split('').reverse().join('')
            )
        .valueOf()    
);

console.log(
    Id(10)
        .map((n:number) => n+10)
        .map((n:number) => n -3)
        .valueOf()
);

console.log(
    Id({ name: 'Tim Jones', age: 45 })
        .map((p:any) => ({ ...p , ...{ statement: `${p.name} is ${p.age} years old` } }) )
        .valueOf()
)