Useful Redux / Ramda functionalities

indexUpdates.js

import { insert, remove, reject } from 'ramda';

// function _insertItem(array, action) {
// 	return [
// 		...array.slice(0, action.index),
// 		action.item,
// 		...array.slice(action.index)
// 	];
// }
const insertItem = (array, action) => insert(action.index, action.item, array);

// function _removeItem(array, action) {
// 	return [...array.slice(0, action.index), ...array.slice(action.index + 1)];
// }

const removeItem = (array, action) => remove(action.index, 1, array);

const items = [
	{ id: 1 },
	{ id: 2 },
	{ id: 3 },
	{ id: 4 },
	{ id: 5 },
	{ id: 6 }
];

insertItem(items, { index: 3, item: { id: 7 } });
removeItem(items, { index: 3 });

updateById.js

import { adjust, findIndex, reject, eqProps, propEq } from 'ramda';

const items = [
	{ id: 1, text: 'Clojure' },
	{ id: 2, text: 'Haskell' },
	{ id: 3, text: 'Elm' },
	{ id: 4, text: 'JS' },
	{ id: 5, text: 'ReasonML' },
	{ id: 6, text: 'Java' }
];

const findIndexById = (id, state) => findIndex(propEq('id', id), state);

const updateItemById = (state, action) =>
	adjust(
		item => ({ ...item, text: action.text }),
		findIndexById(action.id, state),
		state
	);

const removeItemById = (state, action) => reject(eqProps('id', action), state);

// removes the item { id: 5, text: 'ReasonML' } to {id: 5, text: "OCaml"}
updateItemById(items, { id: 5, text: 'OCaml' });
// removes the item { id: 5, text: 'ReasonML' }
removeItemById(items, { id: 5 });