交换嵌套三元表达式以使用ramda.js进行转换

Question

I have working code using nested ternary expressions. Is there any way to make it cleaner using ramda.js or another functional helper? Will cond be a good choice?

I'm new to ramda and I don't know exactly how to convert that piece of code to ramda way.

  const enhance: React$HOC<*, InitialProps> = compose(
      withProps(props => ({
        iconColor: props.isPriority ? (props.isCompleted ? variables.color.lightpurple : variables.color.purple ) : variables.color.gray3,
        iconName: props.isPriority ? 'star-full' : 'star-empty',
      }))
    )

converting just that insane long line:

iconColor: props.isPriority ? (props.isCompleted ? variables.color.lightpurple : variables.color.purple ) : variables.color.gray3,

would be more than enougth.

Answer 1

R.cond is definitely one option for removing the nesting. This could also be combined with R.applySpec to produce an object whose values are all derived from the same argument ( props in your instance).

const enhance: React$HOC<*, InitialProps> = compose(withProps(R.applySpec({
    iconColor: R.cond([
        [({ isPriority }) => !isPriority, () => variables.color.gray3],
        [({ isCompleted }) => isCompleted, () => variables.color.lightpurple],
        [() => true, () => variables.color.purple]
    ]),
    iconName: ({ isPriority }) => isPriority ? 'star-full' : 'star-empty'
})))