The constant function from functional programming: it takes a value and returns a function that will return that value:
var constant = require('const') var alwaysA = constant('a'); alwaysA() //= 'a'
Useful to lifting a value into the world of functions, e.g. when using promises:
getUserDetails() .then(getMessageFromUser, constant('User not found'))
Other names it's gone by in the past:
- K combinator