Ramda and TypeScript: Lenses

lens.test.ts

import { lens } from './lens';

test('adds 1 + 2 to equal 3', () => {
  const unique = Symbol('nested')
  expect(lens({
    some: {
      nested: {
        value: unique
      }
    }
  }))
    .toBe(unique);
});

lens.ts

import { view, lensPath } from "ramda";

export function lens(obj: nestedType): Symbol {
  return view<Symbol, nestedType>(lensPath<Symbol, nestedType>(['some', 'nested', 'value']), obj)
}

nestedType.ts

interface nestedType {
  some: {
    nested: {
      value: Symbol
    }
  }
}