typescriptify-golang-structs

README

A Golang JSON to TypeScript model converter

Installation

The command-line tool:

go get github.com/tkrajina/typescriptify-golang-structs/tscriptify

The library:

go get github.com/tkrajina/typescriptify-golang-structs

Usage

Use the command line tool:

tscriptify -package=package/with/your/models -target=target_ts_file.ts Model1 Model2

If you need to import a custom type in Typescript, you can pass the import string:

tscriptify -package=package/with/your/models -target=target_ts_file.ts -import="import { Decimal } from 'decimal.js'" Model1 Model2

If all your structs are in one file, you can convert them with:

tscriptify -package=package/with/your/models -target=target_ts_file.ts path/to/file/with/structs.go

Or by using it from your code:

converter := typescriptify.New().
    Add(Person{}).
    Add(Dummy{})
err := converter.ConvertToFile("ts/models.ts")
if err != nil {
    panic(err.Error())
}

Command line options:

$ tscriptify --help
Usage of tscriptify:
-backup string
        Directory where backup files are saved
-package string
        Path of the package with models
-target string
        Target typescript file

Models and conversion

If the Person structs contain a reference to the Address struct, then you don't have to add Address explicitly. Only fields with a valid json tag will be converted to TypeScript models.

Example input structs:

type Address struct {
    Duration float64 `json:"duration"`
    Text1    string  `json:"text,omitempty"`
    // Ignored:
    Text2 string `json:",omitempty"`
    Text3 string `json:"-"`
}

type Dummy struct {
    Something string `json:"something"`
}

type Person struct {
    Name      string    `json:"name"`
    Nicknames []string  `json:"nicknames"`
    Addresses []Address `json:"addresses"`
    Dummy     Dummy     `json:"a"`
}

Generated TypeScript:

class Dummy {
        something : string;
}
class Address {
        duration : number;
        text : string;
}
class Person {
        name : string;
        nicknames : string[];
        addresses : Address[];
        a : Dummy;
}

In TypeScript you can just cast your javascript object in any of those models:

var person = <Person> {"name":"Me myself","nicknames":["aaa", "bbb"]};
console.log(person.name);
// The TypeScript compiler will throw an error for this line
console.log(person.something);

Custom Typescript code

Any custom code can be added to Typescript models:

class Address {
        street : string;
        no : number;
        //[Address:]
        country: string;
        getStreetAndNumber() {
            return street + " " + number;
        }
        //[end]
}

The lines between //[Address:] and //[end] will be left intact after ConvertToFile().

If your custom code contain methods, then just casting yout object to the target class (with <Person> {...}) won't work because the casted object won't contain your methods. In that case use the constructor:

converter := typescriptify.New().
    Add(Address)

The TypeScript code will now be:

export class Person {
    name: string;
    nicknames: string[];
    addresses: Address[];
    address: Address;
    metadata: {[key:string]:string};
    friends: Person[];
    a: Dummy;

    constructor(source: any = {}) {
        if ('string' === typeof source) source = JSON.parse(source);
        this.name = source["name"];
        this.nicknames = source["nicknames"];
        this.addresses = source["addresses"] && source["addresses"].map((element: any) => new Address(element));
        this.address = source["address"] && new Address(source["address"]);
        this.metadata = source["metadata"];
        this.friends = source["friends"] && source["friends"].map((element: any) => new Person(element));
        this.a = source["a"] && new Dummy(source["a"]);
    }

    //[Person:]

    yourMethod = () => {
        return "name:" + this.name;
    }

    //[end]
}

And now, instead of casting to Person you need to:

var person = new Person({"name":"Me myself","nicknames":["aaa", "bbb"]});

If you use golang JSON structs as responses from your API, you may want to have a common prefix for all the generated models:

converter := typescriptify.New().
converter.Prefix = "API_"
converter.Add(Person{})

The model name will be API_Person instead of Person.

Custom types

If your field has a type not supported by typescriptify which can be JSONized as is, then you can use the ts_type tag to specify the typescript type to use:

type Data struct {
    Counters map[string]int `json:"counters" ts_type:"{[key: string]: number}"`
}

...will create:

export class Data {
        counters: {[key: string]: number};
}

If the JSON field needs some special handling before converting it to a javascript object, use ts_transform. For example, Dates can be handles this way:

type Data struct {
    Time time.Time `json:"time" ts_type:"Date" ts_transform:"new Date(__VALUE__)"`
}

Generated typescript:

export class Date {
	time: Date;

    constructor(source: any = {}) {
        if ('string' === typeof source) source = JSON.parse(source);
        this.time = new Date(source["time"]);
    }
}

In this case, you should always use new Data(json) instead of just casting <Data>json.

If you use a custom type that has to be imported, you can do the following:

converter := typescriptify.New()
converter.AddImport("import Decimal from 'decimal.js'")

This will put your import on top of the generated file.

Enums

There are two ways to create enums.

Enums with TSName()

In this case you must provide a list of enum values and the enum type must have a TSName() string method

type Weekday int

const (
	Sunday Weekday = iota
	Monday
	Tuesday
	Wednesday
	Thursday
	Friday
	Saturday
)

var AllWeekdays = []Weekday{ Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, }

func (w Weekday) TSName() string {
	switch w {
	case Sunday:
		return "SUNDAY"
	case Monday:
		return "MONDAY"
	case Tuesday:
		return "TUESDAY"
	case Wednesday:
		return "WEDNESDAY"
	case Thursday:
		return "THURSDAY"
	case Friday:
		return "FRIDAY"
	case Saturday:
		return "SATURDAY"
	default:
		return "???"
	}
}

If this is too verbose for you, you can also provide a list of enums and enum names:

var AllWeekdays = []struct {
	Value  Weekday
	TSName string
}{
	{Sunday, "SUNDAY"},
	{Monday, "MONDAY"},
	{Tuesday, "TUESDAY"},
	{Wednesday, "WEDNESDAY"},
	{Thursday, "THURSDAY"},
	{Friday, "FRIDAY"},
	{Saturday, "SATURDAY"},
}

Then, when converting models AddEnum() to specify the enum:

    converter := New().
        AddEnum(AllWeekdays)

The resulting code will be:

export enum Weekday {
	SUNDAY = 0,
	MONDAY = 1,
	TUESDAY = 2,
	WEDNESDAY = 3,
	THURSDAY = 4,
	FRIDAY = 5,
	SATURDAY = 6,
}
export class Holliday {
	name: string;
	weekday: Weekday;
}

License

This library is licensed under the Apache License, Version 2.0