@showwhat/core

Low-level schemas, parsers, and rule engine for showwhat.

Use @showwhat/core when you want the evaluation primitives without the higher-level convenience API.

Installation

npm install @showwhat/core

Quick start

import { MemoryData, resolve, builtinEvaluators } from "@showwhat/core";

const data = await MemoryData.fromObject({
  definitions: {
    checkout_v2: {
      variations: [{ value: true, conditions: [{ type: "env", value: "prod" }] }, { value: false }],
    },
  },
});

const def = await data.get("checkout_v2");

const result = await resolve({
  definitions: { checkout_v2: def! },
  context: { env: "prod" },
  options: { evaluators: builtinEvaluators },
});
console.log(result.checkout_v2.value); // true

Note: The resolver is strict — evaluators must be passed explicitly. There is no default evaluator set injected automatically.

Features

• Built-in condition types: string, number, datetime, bool, env, startAt, endAt
• Composite conditions with and/or logic
• Custom condition types via evaluator composition
• YAML and JSON parsing with schema validation
• Pluggable data sources (DefinitionReader / DefinitionWriter)
• Typed error hierarchy
• Preset condition shortcuts

Documentation

• Quick Start — installation and first definition
• Conditions — built-in condition types and usage
• Context — runtime context object
• Definitions — definition structure and variations
• Core API — showwhat(), resolve(), parsing, and more
• Errors — error types and when they are thrown
• Custom Conditions — writing your own evaluators
• Custom Data Sources — implementing DefinitionReader
• MemoryData — in-memory data source