update or append element like get_or_create of Django.

updateOrAppend.js

const updateOrAppend = R.curry((comp, value, list) => {
  const index = R.findIndex(comp, list);
  return index < 0 ? R.append(value, list) : R.update(index, value, list);
});

// Usage

const family = [{ name: 'taro', age: 30 }, { name: 'jiro', age: 28 }, { name: 'saburo', age: 26 }];

// 1. update taro in family if included.
updateOrAppend(R.propEq('name', 'taro'), { name: 'taro', age: 32 }, family);
// => [{"age": 32, "name": "taro"}, {"age": 28, "name": "jiro"}, {"age": 26, "name": "saburo"}]

// 1. add shiro to family if not included.
const receiveData = { name: 'shiro', age: 24 };
updateOrAppend(R.propEq('name', 'shiro'), receiveData, family);
// => [{"age": 30, "name": "taro"}, {"age": 28, "name": "jiro"}, {"age": 26, "name": "saburo"}, {"age": 24, "name": "shiro"}]