https://github.com/beenotung/ts-type-check
Check json value based of Typescript type in string
https://github.com/beenotung/ts-type-check
Last synced: 8 months ago
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Check json value based of Typescript type in string
- Host: GitHub
- URL: https://github.com/beenotung/ts-type-check
- Owner: beenotung
- License: bsd-2-clause
- Created: 2019-07-01T17:15:32.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2023-05-04T15:17:37.000Z (over 2 years ago)
- Last Synced: 2024-04-25T18:41:15.479Z (over 1 year ago)
- Language: TypeScript
- Homepage: https://www.npmjs.com/package/ts-type-check
- Size: 37.1 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# ts-type-check
Check json value based of Typescript type in string, throw express-compatible error with 400 statusCode.
[](https://www.npmjs.com/package/ts-type-check)
## Supported Data Type
- string
- number
- boolean
- Date
- null
- object (with required / optional fields)
- Array
- unions
- intersections
- unit types\*
\*: Unit types are the literal value of primitive types, e.g. `true` | `false` | `'str'` | `1`
## Typescript signatures
`checkTsType()` can be used for one-off type checking.
```typescript
/**
* only check for json-compatible types
*
* @throws TypeCheckError if failed
* */
function checkTsType(type: string, data: any, options?: TypeCheckOptions): void
type TypeCheckOptions = {
casualBoolean?: boolean
}
class TypeCheckError extends TypeError {
statusCode = 400
status = 400
message: string
}
```
`parseTsType()` compiles the type string into a TypeChecker.
It is optimized for repeating type checking.
(It is used by `checkTsType()` internally.)
```typescript
function parseTsType(type: Type): TypeChecker
interface TypeChecker {
type: string
check(data: any, options?: TypeCheckOptions): void
}
```
## Example
```typescript
import { checkTsType } from 'ts-type-check'
checkTsType('string', 'Alice')
// no error
checkTsType('{ UserId: string }', { UserId: 'Alice' })
// no error
checkTsType('{ UserId: string }', { UserId: 'Alice', Foo: 'bar' }, 'fail')
// throw exception complaining extra field `Foo`
```
More advanced type using nested object, `|`, and `&` are also supported.
```typescript
import { checkTsType } from 'ts-type-check'
checkTsType(`'y' | 'n'`, 'n')
// no error
checkTsType(`1 | 2`, 1)
// no error
checkTsType(`'y' | 'n'`, 'foo')
// throw exception complaining wrong string value
checkTsType(`1 | 2`, 3)
// throw exception complaining wrong number value
checkTsType(
`{
UserId: string,
Contact: {
Method: 'telegram'
} & ({ UserId: string } | { Tel: string }) | {
Method: 'Email',
Email: string
}
}`,
{
UserId: 'Alice',
Contact: {
Method: 'telegram',
UserId: 'alice',
},
},
)
// no error
checkTsType(
`{
UserId: string,
Contact: {
Method: 'telegram'
} & ({ UserId: string } | { Tel: string }) | {
Method: 'Email',
Email: string
}
}`,
{
UserId: 'Alice',
Contact: {
Method: 'Email',
Email_: 'alice@domain.com',
},
},
)
// throw exception complaining missing field 'Email' (if the field is given, then will complain extra field 'Email_')
```
## License
This project is licensed with [BSD-2-Clause](./LICENSE)
This is free, libre, and open-source software. It comes down to four essential freedoms [[ref]](https://seirdy.one/2021/01/27/whatsapp-and-the-domestication-of-users.html#fnref:2):
- The freedom to run the program as you wish, for any purpose
- The freedom to study how the program works, and change it so it does your computing as you wish
- The freedom to redistribute copies so you can help others
- The freedom to distribute copies of your modified versions to others