## ISO8601

```typescript
type Year = `${number}${number}${number}${number}`;
type Month = `${"0" | "1"}${number}`;
type Day = `${"0" | "1" | "2" | "3"}${number}`;

type DateString = `${Year}-${Month}-${Day}`;

type Hour = `${"0" | "1" | "2"}${number}`;
type Minute = `${"0" | "1" | "2" | "3" | "4" | "5"}${number}`;
type Second = `${"0" | "1" | "2" | "3" | "4" | "5"}${number}`;

type TimeString = `${Hour}:${Minute}:${Second}`;

type Offset = `${"Z" | "+" | "-"}${Hour}:${Minute}`;

type ISO8601 = `${DateString}T${TimeString}${Offset}`;
```

## UUID

```typescript
type UUID = `${number}-${number}-${number}-${number}-${number}`;
```

## URI

```typescript
type URI = string;
```

## Extensions

```typescript
type OrgNamespace = string;
type ExtensionName = string;

type ExtensionsKey = `${OrgNamespace}:${ExtensionName}`;

type Extensions = {
    [key in ExtensionsKey]: any;
}
```