@swind/schema
v2.0.1
Published
TypeScript schema declaration and validation library with static type inference
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@swind/schema
Typescript schema validation with static type inference.
Schemas are a crucial part of a microservices architecture or a detachable application architecture (solarwind). They can serve as contracts between different pieces of an application (frontend, backend, forms) and different services. So schemas should be easily portable, written and read, and that's the goal of this package.
Installation
To install:
npm install @swind/schema
⚠️ IMPORTANT: You must enable strict
mode in your tsconfig.json
. This is a best practice for all TypeScript projects.
// tsconfig.json
{
// ...
"compilerOptions": {
// ...
"strict": true
}
}
Usage
Schema
const addressSchema = createSchema({
street: 'string',
number: 'int?',
});
const schemaDefinition = {
name: 'string', // any string
email: 'email?', // email type - will validate against email regex
age: 'int?', // optional integer
notes: '[int]?',
// declaring an union
unionField: [['string?', '[int]?']],
// represents an enum
letter: ['a', 'b', 'c'],
// more detailed way to define enums
letterOptionalList: {
enum: ['x', 'y', 'z'],
optional: true,
list: true,
},
// using a previous schema as field type
optionalAddress: {
type: addressSchema,
optional: true,
},
// another way to define schema fields
deliveryAddress: {
schema: {
street: 'string',
number: 'int?',
},
},
} as const; // "as const" is needed to TS to infer types correctly
const userSchema = createSchema(schemaDefinition);
expect(() => userSchema.parse({ name: 'Antonio', letter: 'x' })).toThrow(
`field "letter": accepted: 'a' or 'b' or 'c', found x.`
);
expect(() => userSchema.parse({ name: 'antonio', letter: 'a', deliveryAddress: {} })).toThrow(
'field "deliveryAddress": ➤ field "street": expected type string, found undefined.'
);
const parsed = userSchema.parse({ name: 'antonio', letter: 'a', deliveryAddress: { street: 'alameda' } });
type InferType = typeof parsed;
assert<
IsExact<
InferType,
{
name: string;
email?: string | undefined;
age?: number | undefined;
notes?: number[] | undefined;
unionField?: string | number[] | undefined;
letter: 'a' | 'b' | 'c';
letterOptionalList?: ('x' | 'y' | 'z')[] | undefined;
optionalAddress?:
| {
street: string;
number?: number | undefined;
}
| undefined;
deliveryAddress: {
street: string;
number?: number | undefined;
};
}
>
>(true);
schemaToTypescript
Returns a string of an interface representing a SolarwindSchema;
import { schemaToTypescript } from '@swind/schema/lib/schemaToTypescript';
const interfaceTxt = await schemaToTypescript('User', userSchema);
const interfaceTxt = await schemaToTypescript('User', userSchema);
expect(interfaceTxt).toBe(`
export interface User {
name: string;
email?: Email;
age?: number;
notes?: number[];
unionField?: string | number[];
letter: "a" | "b" | "c";
letterOptionalList?: ("x" | "y" | "z")[];
optionalAddress?: {
street: string;
number?: number;
};
deliveryAddress: {
street: string;
number?: number;
};
}`);
schemaToJSON
Receives a SolarwindSchema and returns a json-schema
import { schemaToJSON } from '@swind/schema/lib/schemaToJSON';
const jsonSchema = schemaToJSON('User', userSchema);
expect(jsonSchema).toEqual({
properties: {
address: {
properties: {
number: {
type: 'integer',
},
street: {
type: 'string',
},
},
required: ['street'],
title: '',
type: 'object',
},
age: {
type: 'integer',
},
email: {
tsType: 'Email',
type: 'string',
},
letter: {
enum: ['a', 'b', 'c'],
title: 'EnumLetterUser',
type: 'string',
},
letterOptionalList: {
items: {
enum: ['x', 'y', 'z'],
title: 'Enum__subLetterOptionalList',
type: 'string',
},
type: 'array',
},
name: {
type: 'string',
},
notes: {
items: {
type: 'integer',
},
type: 'array',
},
},
required: ['name', 'letter'],
title: 'User',
type: 'object',
});
TODO
- [ ] improve documentation