@aurios/jason/src/layers/json-file.ts

A simple, lightweight, and embeddable JSON document database built on Bun.

import { FileSystem } from "@effect/platform";
import { NodeContext } from "@effect/platform-node";
import { Effect, Schema } from "effect";
import { Json } from "./json.js";
import { isStandardSchema } from "../utils.js";
import type { AnySchema } from "./config.js";
import { ValidationError } from "../core/errors.js";

export class JsonFile extends Effect.Service<JsonFile>()("JsonFile", {
  dependencies: [Json.Default, NodeContext.layer],
  effect: Effect.gen(function* () {
    const fs = yield* FileSystem.FileSystem;
    const json = yield* Json;

    return {
      /**
       * Reads, parses and decode a JSON file, returning
       * the typed object
       */
      readJsonFile: (path: string, schema: AnySchema) =>
        fs.readFileString(path).pipe(
          Effect.flatMap(json.parse),
          Effect.flatMap((parsedJson) => {
            if (isStandardSchema(schema)) {
              return Effect.tryPromise({
                try: () =>
                  Promise.resolve(schema["~standard"].validate(parsedJson)),
                catch: (e) =>
                  new ValidationError({
                    message: `Validation failed: ${e}`,
                    issues: []
                  })
              }).pipe(
                Effect.flatMap((result) => {
                  if (result.issues) {
                    return Effect.fail(
                      new ValidationError({
                        message: "Validation failed",
                        issues: result.issues as any
                      })
                    );
                  }
                  return Effect.succeed(result.value);
                })
              );
            }
            return Schema.decode(schema as Schema.Schema<any, any>)(parsedJson);
          })
        ),

      /**
       * Encode and serialize an object to a JSON string
       * writes it in a file.
       */
      writeJsonFile: (path: string, schema: AnySchema, data: any) => {
        const validate = isStandardSchema(schema)
          ? Effect.tryPromise({
              try: () => Promise.resolve(schema["~standard"].validate(data)),
              catch: (e) =>
                new ValidationError({
                  message: `Validation failed: ${e}`,
                  issues: []
                })
            }).pipe(
              Effect.flatMap((result) => {
                if (result.issues) {
                  return Effect.fail(
                    new ValidationError({
                      message: "Validation failed",
                      issues: result.issues as any
                    })
                  );
                }
                return Effect.succeed(result.value);
              })
            )
          : Schema.encode(schema as Schema.Schema<any, any>)(data);

        return validate.pipe(
          Effect.flatMap(json.stringify),
          Effect.flatMap((content) => fs.writeFileString(path, content)),
          Effect.asVoid
        );
      }
    };
  })
}) {}