Curry Examples

handleChange.js

const handleChange = (fieldName) => (event) => {
  this.setState(fieldName, event.target.value)
}

<input type="text" onChange={handleChange('email')} ... />

updatingNestedState-2.js

const state = {
  data: {
    balance: 2000,
    transactions: []
  },
  ui: {
    loading: false
  }
}

const newTransaction = {
  id: 1, 
  amount: 3000, 
  note: 'Lunch', 
  type: 'DEPOSIT' , 
  date: Date.now()
}

const addTransaction = (newTransaction) => (prevState) => {
  const nextState = {
    ...prevState,
    data: {
      transactions: [...prevState.data.transactions, newTransaction]
    }
  }
  
  return nextState
}

const createNewTransaction = addTransaction(newTransaction)

console.log(createNewTransaction(state))

console.log(state)

updatingNestedState.js

const state = {
  data: {
    balance: 2000
  },
  ui: {
    loading: false
  }
}

const amountToAdd = 3000

const calculateNewBalance = (amountToAdd) => (state) => {
  const nextState = {
    ...state,
    data: {
      balance: state.data.balance + amountToAdd
    }
  }
  
  return nextState
}

const newBalance = calculateNewBalance(amountToAdd)


console.log(newBalance(state))