@juliancoleman/assoc-by-key

assoc-by-key

A curried function using Ramda that transforms an object of objects into an array of objects, where the key becomes a property of that object. The function will return a new array and will not mutate or destroy the original object.

This function performs the inverse of index-by-key

Install

yarn

yarn add @juliancoleman/assoc-by-key

npm

npm i -S @juliancoleman/assoc-by-key

Setup

This package provides the single function mentioned above. You can specify the key on require, or you can specify a key to assoc by later on.

// initialize without specified key
const assocByKey = require("@juliancoleman/assoc-by-key");

// initialize with specified key at require
const assocById = require("@juliancoleman/assoc-by-key")("id");

// initialize with specified key later
const assocByFirstName = assocByKey("first_name");

Once required and a key is specified, you can then call the function on your data to see the transformation. Again, the function will return a new array and will not mutate or destroy the original object.

Below is an example use on a Promise object returned by a database call:

const assocByKey = require("@juliancoleman/assoc-by-key");

const { getUsers } = appRequire("path/to/API");

(async () => {
  const assocById = assocByKey("id");
  const users = await getUsers();

  /*
  Example `users`

    { "1": { "first_name": "Julian",
              "last_name": "Coleman",
              "email_address": "[e-mail]"
            },
      "2": { "first_name": "Bob",
              "last_name": "Sagget",
              "email_address": "[e-mail]" } }
  */

  if (!users) {
    throw new Error("Unable to retrieve users");
  }

  return assocById(users);

})();

/*
results in the following output

[ { "id": 1,
    "first_name": "Julian",
    "last_name": "Coleman",
    "email_address": "[e-mail]" },
  { "id": 2,
    "first_name": "Bob",
    "last_name": "Sagget",
    "email_address": "[e-mail]" } ]
*/

Alternatively, this same thing can be achieved by doing the following:

API
  .getUser()
  .then(assocByKey("id"))
  .catch(UserNotFoundError, () => 404);