benbenbenbenbenben/typedtuplething.ts

## typedtuplething.ts
type TupleBuilderEx<Constraint = any, Tail extends [...any] = []> = {
  items: Tail,
  add: TupleBuilderAdd<Constraint, Tail>
}

type TupleBuilderAdd<Constraint, Tail extends [...any] = []> = <Head extends Constraint>(head: Head) => TupleBuilderEx<Constraint, [...Tail, Head]>


const tupleBuilderEx = <Constraint = any, Head extends Constraint = Constraint, Tail extends [...any] = []>(head: Head, tail?: Tail): TupleBuilderEx<Constraint, [...Tail, Head]> => {
  return {
    items: [...(tail || []), head] as [...Tail, Head],
    add: (next) => tupleBuilderEx(next, [...(tail || []), head] as [...Tail, Head])
  }
}

const buildTupleBuilder = <Constraint = any>() => {
  return {
    withAdd: <Add extends string>(name: Add) => {
      type ThisTupleBuilder<Tail extends [...any] = []> = (
        {
          items: Tail
        }
      ) & Add extends string ? {
          [key in Add]: <Head extends Constraint>(head: Head) => ThisTupleBuilder<[...Tail, Head]>
        } : never

      const add = <Head extends Constraint = Constraint, Tail extends [...any] = []>(head: Head, tail?: Tail): ThisTupleBuilder<[...Tail, Head]> => {
        return {
          items: [...(tail || []), head] as [...Tail, Head],
          [name]: (next: Constraint) => add(next, [...(tail || []), head] as [...Tail, Head])
        }
      }

      return { start: add }


    }
  }
}

buildTupleBuilder<{ foo: string }>()
  .withAdd<"then">("then")
  .start({ foo: "", nad: 1 })
  .then({foo:"sdsd", v:9})
  .then({foo:""})
  .items
//^?
	type TupleBuilderEx<Constraint = any, Tail extends [...any] = []> = {
	items: Tail,
	add: TupleBuilderAdd<Constraint, Tail>
	}

	type TupleBuilderAdd<Constraint, Tail extends [...any] = []> = <Head extends Constraint>(head: Head) => TupleBuilderEx<Constraint, [...Tail, Head]>


	const tupleBuilderEx = <Constraint = any, Head extends Constraint = Constraint, Tail extends [...any] = []>(head: Head, tail?: Tail): TupleBuilderEx<Constraint, [...Tail, Head]> => {
	return {
	items: [...(tail \|\| []), head] as [...Tail, Head],
	add: (next) => tupleBuilderEx(next, [...(tail \|\| []), head] as [...Tail, Head])
	}
	}

	const buildTupleBuilder = <Constraint = any>() => {
	return {
	withAdd: <Add extends string>(name: Add) => {
	type ThisTupleBuilder<Tail extends [...any] = []> = (
	{
	items: Tail
	}
	) & Add extends string ? {
	[key in Add]: <Head extends Constraint>(head: Head) => ThisTupleBuilder<[...Tail, Head]>
	} : never

	const add = <Head extends Constraint = Constraint, Tail extends [...any] = []>(head: Head, tail?: Tail): ThisTupleBuilder<[...Tail, Head]> => {
	return {
	items: [...(tail \|\| []), head] as [...Tail, Head],
	[name]: (next: Constraint) => add(next, [...(tail \|\| []), head] as [...Tail, Head])
	}
	}

	return { start: add }


	}
	}
	}

	buildTupleBuilder<{ foo: string }>()
	.withAdd<"then">("then")
	.start({ foo: "", nad: 1 })
	.then({foo:"sdsd", v:9})
	.then({foo:""})
	.items
	//^?