👋🏽 Are you using Morphism for a project or a library ? Please share the way you use it.

[emyann]

Last time, I was thinking about adding more real use cases to the documentation. According to npm, there is a certain amount of downloads, I was wondering how and for what do you use Morphism

Please share you usage or any relevant public link.

example: #33 (comment)

[svgrepus]

Hello, I am using to convert Angular Reactive Forms to model types.

My form object contains

{
  doc: "123",
  nameNickname: "gvsouza"
}

My model is

class User {
  // nameNickname map to :1 of these two bellow, depending of the value of doc
  // if doc.length is > 3, maps to name else maps to nickname
  name?: string;
  nickname?: string;

  // doc maps to one of these two fields bellow (if doc.length>3 ? rg : ft)
  rg?: string;
  ft?: string;
}

For the input example I gave, I wanted:

{
   ft: "123",
   nickname: "gvsouza"
}

Still trying to figure out a way

[svgrepus]

The way I solved is having a function that returns a schema depending on the doc value of the form.

fromSchema() {
    let schema = {};
    if (this.form.get('doc').value.length > 3) {
      schema = {
        rg: 'doc',
        name: 'nameNickname',
      };
    } else {
      schema = {
        ft: 'doc',
        nickname: 'nameNickname'
      };
    }

    return morphism(schema, this.form.value);
  }

I personally don't like it, I would rather have the schema not add the field if I don't return a value from a function.

const schema = {
      ft: (i, s, d) => {
        if (i.doc.length <= 3) {
          return i.doc;
        }
      },
      rg: (i, s, d) => {
        if (i.doc.length > 3) {
          return i.doc;
        }
      },
      nickname: (i, s, d) => {
        if (i.doc.length <= 3) {
          return i.nameNickname;
        }
      },
      name: (i, s, d) => {
        if (i.doc.length > 3) {
          return i.nameNickname;
        }
      },
    };

Don't know which one is worse...Is there another way?

[emyann]

Hello @gvsouza, thank you for sharing your experience with Morphism !

I would prefer using the second approach too. You can make it a bit less verbose using ES6 destructuring

https://repl.it/@yrnd1/PhonyHeartfeltPattern

const input = {
  doc: "123",
  nameNickname: "gvsouza"
}

const schema = {
  ft: ({ doc }) => doc.length <= 3 ? doc : null,
  rg: ({ doc }) => doc.length > 3 ? doc: null,
  nickname: ({ doc, nameNickname }) => doc.length <= 3 ? nameNickname: null,
  name: ({ doc, nameNickname }) => doc.length > 3 ? nameNickname: null,
};

const output = morphism(schema, input)
// =>
// {
//   "ft": "123",
//   "rg": null,
//   "nickname": "gvsouza",
//   "name": null
// }

I would use the first approach if having 2 target models would make more sense, for example:

class UserWithNickname {
  nickname: string;
  ft: string;
}

class UserWithName {
  name: string;
  rg: string;
}

[svgrepus]

The thing is, I didn't want the extra null properties. I ❤️ the project though

[emyann]

@gvsouza This is much appreciated! Don't hesitate to share it around you or ask questions whenever you need it. Thank you! 😃

[davej]

Running into the same issue as @gvsouza. I wonder does a special string constant to remove a key make sense?

import { REMOVE_KEY } from 'morphism';

const schema = {
  ft: ({ doc }) => doc.length <= 3 ? doc : REMOVE_KEY,
  rg: ({ doc }) => doc.length > 3 ? doc: REMOVE_KEY,
  nickname: ({ doc, nameNickname }) => doc.length <= 3 ? nameNickname : REMOVE_KEY,
  name: ({ doc, nameNickname }) => doc.length > 3 ? nameNickname : REMOVE_KEY,
};

[emyann]

@davej I understand the point. What do you think if I add a new option to the schema allowing to strip null values and any other values as a post processing transformation ? Please look at this issue where I added an option to strip undefined values #52 (comment) and let me know what you think about it.

[davej]

Perfect, thanks Yann.