compose-props

recompose minus react dependency... ish

Each compose-props method has the same argument signature of (state, props) and should return a new 'props' object.

state and/or the first argument stays consistent.

composeProps(...functions)

You can 'compose' compose-props methods using composeProps, but it is not a standard compose function.

Each function you pass to composeProps will be called with (state, props) and should return a new 'props' object.

state should be considered immutable and will consistently be the first argument to every function composed with composeProps.

composeProps calls each passed function from left to right(top to bottom) with the same state but with the previous functions returned 'props' object as the new props.

NOTE If the value null is returned from any of the composed functions, the composeProps will short circuit, and return an empty object{}.

React Native

At Craftsy we are using this library both on the web and on ios/android with React Native.

For this reason we use the setStateTypes and setPropTypes checkers as fail safes that return and empty object{} from composeProps when there is a state/prop type error.

setStateTypes / setPropTypes - object value checkers

These can and probably should be used for your input contract to composeProps and your output contract. They are based off react propTypes and require the same method signature, function(props, propName, componentName).

NOTE: These object value checkers will short circuit if an error is found, console.warn() the error, and finally return null.

Example

example use with react-redux connect:

import {composeProps, setStateTypes, setPropTypes, mapStateToProps, mapPropsOnChange} from 'compose-props';\
import {connect} from 'react-redux';
import {PropTypes} from 'react';
import View from './View.jsx';

const computedProps = composeProps(
  setStateTypes({
    items: PropTypes.arrayOf(PropTypes.shape({
      id: PropTypes.string.isRequired,
    })).isRequired,
  }),
  setPropTypes({id: PropTypes.string.isRequired}),
  mapStateToProps((state, props) => {
    return {thing: state.items.filter((item)=>item.id === props.id)[0]};
  }),
  mapPropsOnChange(['thing'], (state, {thing}) => {
    return {thing, extra: 'added prop'};
  })
);

export default connect(computedProps)(View);