Building your own schema

How the validate key works

Inside your env.config.ts there's an available validate key that you can fill with any object that follows the Standard Schema interface:

types.d.ts

export interface StandardSchemaV1<Input = unknown, Output = Input> {
  readonly "~standard": {
    readonly version: 1;
    readonly vendor: string;
    readonly validate: (value: unknown) =>
      | Promise<{ value: Output } | { issues: { message: string; path?: PropertyKey[] }[] }>
      | { value: Output }
      | { issues: { message: string; path?: PropertyKey[] }[] };
  };
}

Integrating ClassValidator

ClassValidator doesn't follow the Standard Schema interface, but you can easily integrate it by creating a wrapper:

env.config.ts

import 'reflect-metadata';
import { config, providers, UnsafeEnvironmentVariables } from "fatima";
import { validate, IsString, MinLength } from "class-validator";

class Env {
  @IsString()
  @MinLength(12)
  ADMIN_PASSWORD!: string;
}

const createClassValidatorSchema = (schema: new () => object) => ({
  "~standard": {
    version: 1,
    vendor: "class-validator",
    async validate(value: unknown) {
      const instance = Object.assign(new schema(), value);
      const errors = await validate(instance);

      if (errors.length > 0) {
        return {
          issues: errors.map((error) => ({
            message: Object.values(error.constraints ?? {}).join(", "),
            path: error.propertyPath ? [error.propertyPath] : undefined,
          })),
        };
      }

      return { value: instance };
    },
  },
});

export default config({
  providers: {
    development: providers.local(".env"),
  },
  schema: createClassValidatorSchema(Env),
});

Validate

To validate, just run the validate command:

npm fatima validate

pnpm fatima validate

yarn fatima validate

Building your own schema

How the validate key works

Integrating ClassValidator

Validate

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