feat(json-schema): adding types

[cndMarcel]

What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

This PR expands the returned types by adding date and time type formats.

What is the current behavior? (You can also link to an open issue here)

If your JSON Schema defines a property like { "type": "string", "format": "time" }, then Formly returns the type "string" only.
This means that you don't know if the returned property is supposed to be displayed as a regular input field (current standard behaviour), a time field or a date field.

What is the new behavior (if this is a feature change)?

Formly now additionally returns the types time or date if the JSON Schema provides properties with the formats time or date respectively.

According to the latest JSON Schema draft an extension of the instance type is possible:

"Note that JSON Schema vocabularies are free to define their own extended type system."
https://json-schema.org/draft/2019-09/json-schema-core.html#rfc.section.4.2.1

Please check if the PR fulfills these requirements

• The commit messages follow our guidelines: https://github.com/angular/angular.js/blob/master/CONTRIBUTING.md#commit-message-format
• A unit test has been written for this change.
• Running npm run build produced a successful build. (Unit testing can be done by running npm test;)
• My code has been linted. (npm run lint to do this. npm run build will fail if there are files not linted.)

Other information:

In case this is classified as a breaking change you could add a flag like "extended instance types" that makes it possible to return string, time and date instead of only string?

[netlify]

Deploy preview for formly-dev ready!

Built with commit 8545ea6

https://deploy-preview-2056--formly-dev.netlify.com

[aitboudad]

We should restrict this to the date & time only and check if the type is defined else we should fallback to the Native type by setting type to the templateOptions:

{
  type: 'string',
  templateOptions: {
    type: 'date', // 'time' | 'datetime',
  }
}

[cndMarcel]

So would changing the implementation to something like this be sufficient?

if (type === 'string' && (format === 'date' || format === 'time')) {
  return format;
}

I don't quite understand your point about the templateOptions. Should they be changed as well?

[aitboudad]

Note: Just in case you don't know/ or want this feature asap, a map options can be used to adjust the generated FormlyFieldConfig #1982 (comment).

[indiealexh]

This feature is important to me. Anything I can do to help progress this PR?

[aitboudad]

@indiealexh see #2222 (comment)

[menosprezzi]

@aitboudad I'll restart this PR since the original author does not have applied the suggested changes, ok?