Started using ESLint and running into couple of issues with PropType, currently I have a prop children and for now let's say this prop is a string. I'm getting an error 'children' is missing in props validationeslint(react/prop-types), to solve this I just use PropTypes like so:

CartProvider.propTypes = {
  children: PropTypes.string,
}

The above solves the issue and then I get another issue propType "children" is not required, but has no corresponding defaultProps declaration.eslint(react/require-default-props)

So to solve this I add another PropType like so:

CartProvider.defaultProps = {
  children: PropTypes.string,
}

So my understanding is that every time I use a prop I need to use propType and defaultProps. So ok this solves the issue with string based prop. But actually this prop is an array and then with array I'm getting other issues Prop typearrayis forbiddeneslint(react/forbid-prop-types).

Please help me understand why does ESLint marking these props as errors, I know how to disabled it but I would like to understand why it's happening and then write better code.

Here is a sample project:

CartContext

import React from 'react'
import PropTypes from 'prop-types'

export const CartContext = React.createContext(null)

export const CartProvider = ({ children }) => {
  const [cartTotal, setCartTotal] = React.useState(0)
  const incrementCartTotal = () => setCartTotal(cartTotal + 1)

  return (
    <CartContext.Provider
      value={{
        cartTotal,
        incrementCartTotal,
      }}
    >
      {children}
    </CartContext.Provider>
  )
}

CartProvider.propTypes = {
  children: PropTypes.string,
}

CartProvider.defaultProps = {
  children: PropTypes.string,
}

App

import React from 'react'
import { CartContext, CartProvider } from './CartContext'

function CartTotalItems() {
  const { cartTotal } = React.useContext(CartContext)
  return (
    <p>
      Total items currently in cart:
      {cartTotal}
    </p>
  )
}

function AddToCart() {
  const { incrementCartTotal } = React.useContext(CartContext)
  return (
    <button type="button" onClick={incrementCartTotal}>
      Add to cart
    </button>
  )
}

export default function App() {
  return (
    <CartProvider>
      <CartTotalItems />
      <AddToCart />
    </CartProvider>
  )
}

Update This has worked for me, remove the 2 PropTypes and add this:

CartProvider.propTypes = {
  children: PropTypes.node.isRequired,
}

Started using ESLint and running into couple of issues with PropType, currently I have a prop children and for now let's say this prop is a string. I'm getting an error 'children' is missing in props validationeslint(react/prop-types), to solve this I just use PropTypes like so:

CartProvider.propTypes = {
  children: PropTypes.string,
}

The above solves the issue and then I get another issue propType "children" is not required, but has no corresponding defaultProps declaration.eslint(react/require-default-props)

So to solve this I add another PropType like so:

CartProvider.defaultProps = {
  children: PropTypes.string,
}

So my understanding is that every time I use a prop I need to use propType and defaultProps. So ok this solves the issue with string based prop. But actually this prop is an array and then with array I'm getting other issues Prop typearrayis forbiddeneslint(react/forbid-prop-types).

Please help me understand why does ESLint marking these props as errors, I know how to disabled it but I would like to understand why it's happening and then write better code.

Here is a sample project:

CartContext

import React from 'react'
import PropTypes from 'prop-types'

export const CartContext = React.createContext(null)

export const CartProvider = ({ children }) => {
  const [cartTotal, setCartTotal] = React.useState(0)
  const incrementCartTotal = () => setCartTotal(cartTotal + 1)

  return (
    <CartContext.Provider
      value={{
        cartTotal,
        incrementCartTotal,
      }}
    >
      {children}
    </CartContext.Provider>
  )
}

CartProvider.propTypes = {
  children: PropTypes.string,
}

CartProvider.defaultProps = {
  children: PropTypes.string,
}

App

import React from 'react'
import { CartContext, CartProvider } from './CartContext'

function CartTotalItems() {
  const { cartTotal } = React.useContext(CartContext)
  return (
    <p>
      Total items currently in cart:
      {cartTotal}
    </p>
  )
}

function AddToCart() {
  const { incrementCartTotal } = React.useContext(CartContext)
  return (
    <button type="button" onClick={incrementCartTotal}>
      Add to cart
    </button>
  )
}

export default function App() {
  return (
    <CartProvider>
      <CartTotalItems />
      <AddToCart />
    </CartProvider>
  )
}

Update This has worked for me, remove the 2 PropTypes and add this:

CartProvider.propTypes = {
  children: PropTypes.node.isRequired,
}

• javascript
• reactjs
• eslint
• react-proptypes

2 Answers 2

You are mistaking the type of children and confuses the use of defaultProps:

// Use for initial value
CartProvider.defaultProps = {
  counter: 10,

/* 
  You declared the initial value to be the value of `PropTypes.string`
  children: PropTypes.string
*/
}

// Children are always an Array of `ReactElement`/ `ReactElement` node.
CartProvider.propTypes = {
  counter: PropTypes.number,

  children: PropTypes.node.isRequired,

/* Same
  children: PropTypes.oneOfType([
        PropTypes.arrayOf(PropTypes.node),
        PropTypes.node
    ]).isRequired
*/

/*
  props.children can't be a string.
  children: PropTypes.string,
*/
}

defaultProps should be set a value instead of using Proptypes again

CartProvider.propTypes = {
  children: PropTypes.string,
}

CartProvider.defaultProps = {
  children: "This is chidlren default string"
}