yarn add ts-guard-clause
Before:
if (body.name !== undefined) {
throw new Error('Name is undefined')
}
console.log(name)After:
const name = Guard.against.undefined(body.name)
console.log(name)Shorter version:
const name = Against.undefined(body.name)
console.log(name)Add a custom message/error
Guard.against.undefined(body.name, 'Custom Error')
// OR
Guard.against.undefined(body.name, new MyCustomError('Some Error'))- null
- undefined
- nullish (null and undefined)
- nullishOrEmpty (null, undfined, not an empty array)
- expression (custom condition)
First you will need to extend the IGuardClause interface:
// @types/ts-guard-clause/index.d.ts
import 'ts-guard-clause'
declare module 'ts-guard-clause' {
interface IGuardClause {
hello<T>(prop: T): T
}
}If everything went well then the AddExtension method will give you intellisense for the hello clause.
import { Guard, GuardFactory } from 'ts-guard-clause'
GuardFactory.AddExtension('hello', (prop) => prop === 1)
Guard.against.Hello('hello') // Throws