Closure notes

closure.js

function bookSlotByCustId(customerId) {
  const custId = customerId

  return function bookSlot(slotId) {
    //psuedo code here:
    dispatch({
      apiCall: api.bookSlot(custId, slotId)
    });
  }
}

const cId = 5

const bookMySlot = bookSlotByCustId(cId);
// bookMySlot is *just* a function

// assume "time has passed here"
// what i really mean is - we have lost the context of our cId variable


const sId = 6
bookMySlot(sId)


const InTrolleyCounter = (styleModifier, amountSuffix) => ({ productName, quantity }) => {
    // do something with all 4 varaiables
}

function InTrolleyCounter (styleModifier, amountSuffix) {
  return function({ productName, quantity }) {
    // do something with all 4 varaiables
  }
}

// we have stored 'style' and 'amount' at this point - they are bound to x now.
const x = InTrolleyCounter('style', 'amount')
// here we pass in the second set of args, which we can change whenever we call x
x('name', 1)

export default {
  RoundelTrolleyCounter: InTrolleyCounter('roundel', ''),
  BannerTrolleyCounter: InTrolleyCounter('', ' in trolley'),
  AdaptiveBannerTrolleyCounter: InTrolleyCounter('adaptToViewport', ' in trolley'),
}

...

import ITC from 'introlleycounter';

const Roundel = ITC.RoundelTrolleyCounter;

Roundel('fred', '1')

render() {
  return (<Roundel productName='fred' quantity='1' />)
};