extending the svelte store writable with your own methods

extending-svelte-store-writable.js

const { writable, get } = require("svelte/store");
const merge = require("lodash/merge");

/**
 * A svelte store writable with two extra methods
 *
 * Usage:
 * const store = customStore({ name: "Erasmus" });
 * store.merge({ name: "Billy" });
 * store.reset();
 *
 * @param defaultValue
 */
function customStore(defaultValue){
  const op = writable(defaultValue)
  op.merge = obj => op.set(merge(get(op), obj));
  op.reset = () => op.set(defaultValue);
  return op;
}

modex.exports = customStore;