typemallow 2

An elegant and automatic solution for generating/outputting Typescript interfaces from your Marshmallow Schemas

I updated the typemallow package so it could Handle enums in typescript and more recent versions of marshmallow. Original work is from adenh93.

Usage:

Using typemallow2 is simple.

First, install the package pip install typemallow2

Next, for your Marshmallow schemas that you wish to generate Typescript interfaces for, simply import ts_interface and generate_ts from the typemallow module, and prepend the @ts_interface() class decorator to your Marshmallow schema class.

All that is required to generate your Typescript interfaces is to call the generate_ts() function, and provide a filepath as a parameter to output the result.

main.py

from typemallow2 import ts_interface, generate_ts


@ts_interface()
class Foo(Schema):
    some_field = fields.Str()
    another_field = fields.Date()


generate_ts('./output.ts')

output.ts

export interface Foo {
    some_field: string;
    another_field: date;
}

typemallow even supports Nested Schema fields and enums.

main.py

from typemallow2 import ts_interface, generate_ts, ts_enum
from marshmallow import Schema, fields
from marshmallow_enum import EnumField
from enum import Enum, auto


@ts_enum(value_is_auto=True)
class MyAutoEnum(Enum):
    enum1 = auto()
    enum2 = auto()

@ts_enum(value_is_auto=False)
class MyNonAutoEnum(Enum):
    enum1 = 100
    enum2 = 200
    enum3 = "Baguette"

@ts_interface()
class Boo(Schema):
    some_field = fields.Str()
    my_enum_field = EnumField(MyAutoEnum)


@ts_interface()
class Foo(Schema):
    some_field = fields.Str()
    another_field = fields.Str()
    my_field = fields.Bool()
    my_interface_field = fields.Nested(Boo, many=False)

generate_ts('./output.ts')

output.ts

export enum MyAutoEnum {
	enum1,
	enum2,
}

export interface Bar {
	some_field: string;
	my_enum_field: MyAutoEnum;
}

export interface Foo {
	some_field: string;
	another_field: string;
	my_field: boolean;
	my_interface_field: Bar;
	my_interfaces_fields: Bar[];
}

Extended Usage:

The @ts_interface() decorator function accepts an optional parameter, context, which defaults to... well... 'default'.

"Why is this the case?"

When a Marshmallow Schema is identified with with @ts_interface decorator, it is added to a list in a dictionary of schemas, with the dictionary key being the value provided to the context parameter. If you were to provide different contexts for each schema, additional keys will be created if they do not exist, or the schema will simply be appended to the list at the existing key.

This comes in handy, as the generate_ts() function also accepts an optional context parameter, which will filter only schemas in the dictionary at the specific key.

This is useful if you wish to output different contexts to different files, e.g.

main.py

...
from typemallow2 import ts_interface, generate_ts

@ts_interface(context='internal')
class Foo(Schema):
    foo = fields.Str()


@ts_interface(context='internal')
class Bar(Schema):
    bar = fields.Str()
 

@ts_interface(context='external')
class FooBar(Schema):
    foo_bar = fields.Str()


''' 
we're telling typemallow2 that we only want to generate interfaces from Schemas with 
an 'internal' context to './internal.ts' 
'''
generate_ts('./internal.ts', context='internal')

''' 
only generate interfaces from Schemas with an 'external' context to './external.ts' 
'''
generate_ts('./external.ts', context='external')

internal.ts

export interface Foo {
    foo: string;
}

export interface Bar {
    bar: string;
}

external.ts

export interface FooBar {
    foo_bar: string;
}