Help converting a complex json object

[iangregsondev]

Hi,

I have a json object, its not complex but what I want to end up, is a little difficult for me to understand how to do this. The standard JSON object (represented by a typescript interface) is this

{
  "_embedded": {
    "record": {
      "name": "CompanyA",
      "meta": {
        "address": "6 some street",
        "stateCountry: "NY, USA"
      }
    }
  },
  "pageData": {
    "pagination" : {
      "page": 1,
      "totalPages": 1
    }
  }
}

I want to end up with the following, represented by a typescript class

export class Item {
   name: string // this comes from __embedded/record/name
   address: string // this comes from __embedded/record/meta/address
   state: string // this comes from __embedded/meta/stateCountry (split by coma, FIRST part)
   country: string // this comes from __embedded/meta/stateCountry (split by coma, SECOND part)
  pagination : Pagination 
}

export class Pagination {
    page: number //this comes from __embedded/pageData/pagination/page
    totalPages: number //this comes from __embedded/pageData/pagination/totalPages
    hasNext: boolean // this uses the above 2 properties to work out if there is a nextPage, true/false
}

Any help really appreciated

Thanks

[emyann]

Hello @appsolutegeek, thank for using Morphism!

You can achieve what you want using 2 similar approaches:

• Using 1 single schema transforming the source to the Item interface
• Break down your transformations by using 2 nested schemas; 1 schema from source to Pagination and a parent schema from source to Item

Considering the source is:

const source = {
  "_embedded": {
    "record": {
      "name": "CompanyA",
      "meta": {
        "address": "6 some street",
        "stateCountry": "NY, USA"
      }
    }
  },
  "pageData": {
    "pagination": {
      "page": 1,
      "totalPages": 1
    }
  }
}

With 1 single complex schema

const complexSchema = createSchema<Item, typeof source>({
  name: '_embedded.record.name',
  address: '_embedded.record.meta.address', 
  state: ({ _embedded: { record: { meta: { stateCountry } } } }) => stateCountry.split(',')[0], 
  country: ({ _embedded: { record: { meta: { stateCountry } } } }) => stateCountry.split(',')[1], 
  pagination: { 
    page: 'pageData.pagination.page', 
    totalPages: 'pageData.pagination.totalPages', 
    hasNext: ({ pageData: { pagination } }) => !(pagination.page === pagination.totalPages) 
    }
})

morphism(complexSchema, source)

With 2 nested schemas

const paginationSchema: StrictSchema<Pagination, typeof source> = { 
    page: 'pageData.pagination.page', 
    totalPages: 'pageData.pagination.totalPages', 
    hasNext: ({ pageData: { pagination } }) => !(pagination.page === pagination.totalPages) 
}
const nestedSchema = createSchema<Item, typeof source>({
  name: '_embedded.record.name',
  address: '_embedded.record.meta.address', 
  state: ({ _embedded: { record: { meta: { stateCountry } } } }) => stateCountry.split(',')[0], 
  country: ({ _embedded: { record: { meta: { stateCountry } } } }) => stateCountry.split(',')[1], 
  pagination: morphism(paginationSchema) // Map the Pagination object using the schema above
})

morphism(nestedSchema, source)

Here's a working playground if you want to test it: https://stackblitz.com/edit/morphism-single-source-to-complex-destination

Is it what you were looking for ? Please let me know if there are some parts where you need further explanation.

[iangregsondev]

That was perfect! Thank you!

[emyann]

I am trying to type this but it's not an easy one, the only way I found to support this would be to have an array of string representing the property path see microsoft/TypeScript#12290. If you want to make the most of strictly typing you could use a function instead `name: (source) => source._embedded.record.name`, destructuring the object works as well :)

…

On Tue, 9 Apr 2019 at 06:13, Ian Gregson ***@***.***> wrote: Just one question, this line name: '_embedded.record.name', Is it possible to keep it strictyly typed, i mean instead of passing in a string as its prone to error. i.e. _embedded.record.name — You are receiving this because you were assigned. Reply to this email directly, view it on GitHub <#60 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AEh0g1VqnPv4yacuXM8NvkAdeLssg0Jvks5vfGfdgaJpZM4ciV4E> .

-- Yann RENAUDIN <http://linkedin.com/in/renaudinyann> | Développeur et Architecte de solutions | * renaudin.yann@gmail.com | +33629826437

[iangregsondev]

Sorry @emyann , I think that was a comment I left previously, I actually deleted it because sure enough, it was as easy as that.

Although it got it on iteretee

  totalPages: iteratee => iteratee.page.totalPages,

[emyann]

Perfect, thank you! Closing this one :)