@fulcro/types

Numeric types with a declared range and layout: fixed-width integers, half, single and double precision floats, an integer of any size, and a Decimal with the semantics of IEEE 754 decimal128. Nothing to configure: every operation is a typed method.

npm install @fulcro/types

import { Decimal, SignedInteger, UnsignedInteger } from '@fulcro/types';

const Int32 = SignedInteger(32);

Int32.add(Int32.from(2), Int32.from(3)); // 5
Int32.add(Int32.maximum, Int32.from(1)); // RangeError: FULCRO6031: … outside [-2147483648, 2147483647]
UnsignedInteger(8).wrap(-1); // 255, when modular arithmetic is what you mean

Decimal.from('0.1').add(Decimal.from('0.2')).toString(); // '0.3'
Decimal.from('19.99').multiply(Decimal.from(3)).toString(); // '59.97'

| Type | What it is | | -------------------------------------------- | -------------------------------------------------- | | SignedInteger<N>, UnsignedInteger<N> | 8 to 128 bits, checked arithmetic, wrap | | HalfPrecisionFloat, SinglePrecisionFloat | binary16 and binary32, each operation rounded once | | DoublePrecisionFloat | binary64, the number named as a choice | | BigInteger | an integer of any size | | Decimal | 34 decimal digits, five rounding modes |

Each type has a value of the same name that converts, recognises and computes, and every type but BigInteger reports its minimum and maximum. If you only need the types, import type them and no code is loaded.

The JavaScript operators are the language's own: a + b on two SignedInteger<32> is a plain, unchecked number, and on a Decimal it throws. Use the methods, which keep the type and its checks.

Every type but BigInteger declares a size and alignment, which sizeOf<T>() and alignOf<T>() from @fulcro/reflect read at compile time.

Structs

Value types with a fixed layout, built from the types above and from each other — frozen, compared by field, and stored in a DataView without an object per value:

import { SinglePrecisionFloat, struct, type Struct } from '@fulcro/types';

const Vector3 = struct('Vector3', {
	x: SinglePrecisionFloat,
	y: SinglePrecisionFloat,
	z: SinglePrecisionFloat,
});
type Vector3 = Struct<typeof Vector3>;

Vector3.layout.size; // 12, and sizeOf<Vector3>() at compile time
Vector3.write(view, 0, Vector3.from({ x: 0, y: 1, z: 0 }));

Full guide: docs/types.md — ranges, rounding, the special values, the layout table and structs. 🇧🇷 Leia em português.