Expressen Pipeline Map

An interface to make transformations of javascript object structures more streamlined and easier to read. The main goal is to provide a better experience and let developers develop faster.

How to

Simply start the pipeline by requiring the lib and "pressing start" followed by your actions:

const Mapper = require("exp-pipeline-map");

const input = {
  name: "José",
  lastName: "Armstrong",
  gender: null,
  age: 32,
  interests: ["Coding", "Drinking", "Slacking"]  
};

Mapper.pipe(input)
  .select("name", "lastName", "interests")
  .mapOn("interests", (interest) => interest.toLowerCase())
  .filterOn("interests", (interest) => interest !== "slacking")
  .add("initials", (object) => `${object.name[0]}${object.lastName[0]}`)
  .then((output) => {
    console.log(output)
    /**
      {
        name: "José",
        lastName: "Armstrong",
        initials: "JA",
        interests: ["coding", "drinking"]
      }
    */
  })

Available methods

pipe(value)

Used for starting the mapping chain. It is an alias of resolve.

select(key[, ...keys])

Filters the current objects properties in a selective manner

delete(key[, ...keys])

Filter the current objects properties in an excluding manner

mapOn(key, fn)

Maps a collection with given method

filterOn(key, fn)

Filters a collection with given method. Note that this method is supposed to return a boolean where true means keep and false means do not keep.

modify(key, fn|value)

Transforms a key with a method taking the value as first argument or a direct value

rename(key, newName)

Renames a key

add(key, fn|value)

Adds a property to the object. It will either be a direct value or the result of the provided method. Will handle returned promises.

tap(fn)

Executes the provided method but discards it's returned value and instead pipes through the object as is. Very useful for logging or out of band operations.

Whats going on

Basically this is just an extension of the regular Promise with some sugarcoating that provides clear methods to prevent having to type .then all the time.