[Ramda] Pick and Omit Properties from Objects Using Ramda

Sometimes you just need a subset of an object. In this lesson, we'll cover how you can accomplish this using Ramda's pick and omit functions, as well as the pickAll and pickBy variants of pick.

const R = require('ramda');

const {pick, prop, pickBy, pickAll, props, omit, compose, not, curry} = R;

const log = curry((desc, x) => R.tap(() => console.log(desc, JSON.stringify(x, null, 2)), x));

const product = {
    name: 'widget',
    price: 10,
    shippingWeight: 20,
    shippingMethod: 'UPS'
};

// get one single prop from a large object
const getByProp = pick(['name']); // { name: 'widget' }

// different from R.prop
const getPropVal = prop('name'); // 'widget'

const getByProps = pickAll(['name', 'price']); // { name: 'widget', price: 10 }

const getPropsVals = props(['name', 'price']); // [ 'widget', 10 ]

const getByPickBy = pickBy((val, key) => {
    // Only get prop if
    // val: is number
    // key contains 'shipping'
    return Number(val) && key.includes('shipping');
});  // { shippingWeight: 20 }

const omitShippingProps = omit(['shippingWeight', 'shippingMethod']); // { name: 'widget', price: 10 }

// another way to omit props by conditions
const notToPickByShippingProps = pickBy((val, key) => !key.includes('shipping')); // { name: 'widget', price: 10 }


const result = notToPickByShippingProps(product);
console.log(result);