Core TypeScript Record (@luolapeikko/core-ts-record)

Record/object type guards, assertions, mapping utilities, and predicates for TypeScript applications.

Features

• Type guards for record/object validation
• Assertion functions that throw TypeError
• Mapping utilities for object transformation
• Predicate functions for functional programming
• Support for empty objects, key validation, and property checking

Installation

npm install @luolapeikko/core-ts-record

Full documentation

See https://luolapeikko.github.io/core-ts/ for detailed API documentation and usage examples for each package.

Usage

import {
  RecordAssert,
  RecordCore,
  RecordMapper,
  RecordPredicate,
} from "@luolapeikko/core-ts-record";

// Type guards
const value: unknown = { name: "John", age: 30 };

if (RecordCore.is(value)) {
  console.log(`Object keys: ${RecordCore.keys(value)}`); // value is typed as Record<string, unknown>
}

// Assertions
function processRecord(input: unknown) {
  RecordAssert.assert(input);
  return RecordCore.values(input); // input is now typed as record, get values safely
}

// Core utilities
const data = { a: 1, b: 2, c: 3 };
const keys = RecordCore.keys(data); // ['a', 'b', 'c']
const values = RecordCore.values(data); // [1, 2, 3]
const picked = RecordCore.pick(["a", "c"], data); // { a: 1, c: 3 }
const omitted = RecordCore.omit(["b"], data); // { a: 1, c: 3 }

// Mapping utilities
const pickMapper = RecordMapper.pick(["a", "c"]); // Function to pick keys
const propMapper = RecordMapper.prop("name"); // Function to get property
const mappedData = pickMapper(data); // Apply the pick mapper
const testObj = { name: "Test", value: 42 };
const nameValue = propMapper(testObj); // Apply the prop mapper

// Predicates for filtering
const objects = [{ name: "John" }, { name: "Jane" }, { age: 30 }];
const johnObjects = objects.filter(RecordPredicate.propEq("name", "John")); // [{ name: 'John' }]

// Example usage
const testRecord = { foo: "bar", baz: 42 };
const result = processRecord(testRecord);