object-dsl

object-dsl

µ functional library to transverse objects using an extendable DSL-like syntax

Installation

$ npm i --save object-dsl

Examples

Simple transformations

import compile from 'object-dsl'

// Operators
const replace = text => next => node => node.replace('%placeholder%', text)
const toUpper = next => node => node.toUpperCase()

// DSL spec
const dsl = {
  foo: replace('world'),
  obj: {
    name: toUpper
  }
}

// Compile DSL
const compiled = compile(dsl)

// Run with object
const result = compiled({
  foo: 'hello %placeholder%',
  obj: {
    name: 'foobar'
  }
})

console.log(result) // { foo: 'hello world', obj: { name: 'FOOBAR' } }

Composition

import compile from 'object-dsl'

// Operators
const replace = text => next => node => node.replace('%placeholder%', text)
const toUpper = next => node => node.toUpperCase()

// DSL spec
const obj = {
  name: toUpper
}

const dsl = {
  foo: replace('world'),
  obj
}

// Compile DSL
const compiled = compile(dsl)

// Run with object
const result = compiled({
  foo: 'hello %placeholder%',
  obj: {
    name: 'foobar'
  }
})

console.log(result) // { foo: 'hello world', obj: { name: 'FOOBAR' } }

array and map operators

import compile, { array, map } from 'object-dsl'

// Operators
const replace = (placeholder, text) => next => node => node.replace(`%${placeholder}%`, text)
const photo = next => node => `http://image-server.com/files/${node}`

// DSL spec
const dsl = {
  names: (
    array(
      replace('title', 'Mr.')
    )
  ),
  images: (
    map(
      photo
    )
  )
}

// Compile DSL
const compiled = compile(dsl)

// Run with object
const result = compiled({
  names: [
    '%title% John Doe',
    '%title% John Smith'
  ],
  images: {
    cover: 'cover.png',
    back: 'back.png',
    other: 'other.png'
  }
})

console.log(result)

/*
{
  names: [
    'Mr. John Doe',
    'Mr. John Smith'
  ],
  images: {
    cover: 'http://image-server.com/files/cover.png',
    back: 'http://image-server.com/files/back.png',
    other: 'http://image-server.com/files/other.png'
  }
 }
*/

Passing state

import compile, { array, map } from 'object-dsl'

// Operators
const item = next => (node, state) => ({ path: state.path })

// DSL spec
const dsl = {
  types: (
    map(
      array(
        item
      )
    )
  )
}

// Compile DSL
const reducer = (state, { key }) => ({ path: [...state.path, key] })
const initState = { path: ['root'] }
const compiled = compile(dsl, reducer, initState)

// Run with object
const obj = {
  types: {
    type1: [
      { id: 'type1_1' },
      { id: 'type1_2' }
    ],
    type2: [
      { id: 'type2_1' }
    ]
  }
}

const result = compiled(obj)
console.log(result)

/*
{
  types: {
    type1: [
      { path: ["root", "types", "type1", 0] },
      { path: ["root", "types", "type1", 1] }
    ],
    type2: [
      { path: ["root", "types", "type2", 0] }
    ]
  }
}
*/

// ---------
// withMerge
// ---------

import { withMerge } from 'object-dsl'

// Run with object
const result = withMerge(compiled)(obj)
console.log(result)

/*
{
  types: {
    type1: [
      { id: 'type1_1', path: ["root", "types", "type1", 0] },
      { id: 'type1_2', path: ["root", "types", "type1", 1] }
    ],
    type2: [
      { id: 'type2_1', path: ["root", "types", "type2", 0] }
    ]
  }
}
*/

API