如果不是null，则使用ramda js获取值

Question

How i write the code as functional if i has the value like this

const data = {
name: null,
email: null,
username: 'johndoo'
}

in this case if i write the function that return the display name i just wrote data.name || data.email || data.username data.name || data.email || data.username

I try to use ramda like

const getName = R.prop('name')
const getEmail = R.prop('email')
const getUsername = R.prop('username')
const getDisplayName = getName || getEmail || getUsername

but doesn't work, how to write it in ramdajs

Answer 1

You need to use a logical or R.either :

const getDisplayName = R.either(getName, R.either(getEmail, getUsername))

Or more compact with R.reduce :

const getDisplayName = R.reduce(R.either, R.isNil)([getName, getEmail, getUsername])

 const data = { name: null, email: null, username: 'johndoo' } const getName = R.prop('name') const getEmail = R.prop('email') const getUsername = R.prop('username') const eitherList = R.reduce(R.either, R.isNil) const getDisplayName = eitherList([getName, getEmail, getUsername]) console.log(getDisplayName(data)) 

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