@morphism/runtime

A combination of io-ts and io-ts-types, exported under
a namespace called Runtime, that acts as an all-in-one input/output
validation library.

$3

If we have an endpoint that accepts a payload of the following shape:
``typescript
{
username: string;
hoursWorked: string;
isOvertime?: string;
date: number
}
`
and, after parsing/validation, needs to be transformed to:
`typescript
{
username: string;
hoursWorked: number;
isOvertime: boolean;
date: Date
}
`
where
- username is a required parameter that we want a special error message for
- isOvertime is an optional argument we want to fill with a default value when
it isn't provided
- date is a UNIX epoch representing a Date
- hoursWorked is just some number

Then we could use @morphism/runtime to describe the above logic like so:
`typescript
import { Runtime } from "@morphism/runtime";

type Request = Runtime.ToType;
namespace Request {
export const runtime = () =>
Runtime.strict({
username: Runtime.withMessage(
Runtime.string(),
() => 'Some special error message for just username'
),
hoursWorked: Runtime.numberFromString(),
isOvertime: Runtime.withFallback(Runtime.booleanFromString(), false),
dateRange: Runtime.dateFromUnixTime(),
});
}
`
Request now represents the shape our Request.runtime function validates,
and can be used like so:
`typescript
pipe(
input,
Request.runtime().decode,
Either.fold(
(errors: Runtime.Errors) => ...,
(request: Request) => ...
)
)
``