54ed736e28
Adds a simple `checkProp` factory function for re-usable utility predicates. The reason the predicate comes before the prop is to signify the predicate will be called with the prop, however I have no desire to make that a hard requirement. Order can easily be changed.
869 B
869 B
checkProp
Given a predicate function and a prop string this curried function will then take an object to inspect by calling the property and passing it to the predicate.
It summons prop on obj and passes it to a provided predicate function and returns a masked boolean
const checkProp = (predicate, prop) => obj => !!predicate(obj[prop])
const lengthIs4 = checkProp(l => l === 4, 'length')
lengthIs4([]) // false
lengthIs4([1,2,3,4]) // true
lengthIs4(new Set([1,2,3,4]) // false (Set uses Size, not length)
const session = { user: {} }
const validUserSession = checkProps(u => u.active && !u.disabled, 'user')
validUserSession(session) // false
session.user.active = true
validUserSession(session) // true
const noLength(l => l === undefined, 'length')
noLength([]) // false
noLength({}) // true
noLength(new Set()) // true