Composing functions by piping

main.js

const { validate, normalize, persist } = require('./user-module')
const pipe = require('./pipe')

const saveUser = (user) => {
    return pipe(
        validate,
        normalize,
        persist
    )(user)
}

const savedUser = saveUser({
    firstName: 'ervinne',
    lastName: 'sodusta',
})
console.log('user saved', savedUser)

/*
    Prints out:
    validating { firstName: 'ervinne', lastName: 'sodusta' }
    normalizing { firstName: 'ervinne', lastName: 'sodusta' }
    persisting { firstName: 'ervinne', lastName: 'sodusta' }
    user saved { firstName: 'ervinne', lastName: 'sodusta' }
 */

pipe.js

const pipe = (...fns) => { 
    return param => fns.reduce(
        (result, fn) => fn(result), 
        param
    )
}

module.exports = pipe;

user-module.js

//  Note: these are samples only, but if there are real functions here that does mutations, create a new object/clone instead
const UserModule = {
    validate: (user) => {
        console.log('validating', user)
        //  ...
        return user;
    },
    normalize: (user) => {
        console.log('normalizing', user)
        //  ...
        return user;
    },
    persist: (user) => {
        console.log('persisting', user)
        //  ...
        return user;
    },
}

module.exports = UserModule;