ValidatorTS

A TypeScript validator implementation inspired by .NET data annotations like [Required], [Range] etc.

Example

1. Property decorators

Code:

import {
    required,
    range,
    length,
    validate
} from "./validator";

class Human {
    @required("sex is required.")
    sex: string;
}

class Person extends Human {
    @required("name is required.")
    name: string;
    @range(1, 10, "age must be in the range [1, 10].")
    age: number;
    @required("data is required")
    @length(10, 10, "data must be of length 10.")
    data;
}

let person = new Person();
console.log(validate(person));

Result:

[ 'name is required.',
  'age must be in the range [1, 10].',
  'data must be of length 10.',
  'data is required',
  'sex is required.' ]

2. Method decorator

Code:

class Person extends Human {
    @required("name is required.")
    name: string;
    @range(1, 10, "age must be in the range [1, 10].")
    age: number;
    @required("data is required")
    @length(10, 10, "data must be of length 10.")
    data;

    @validated
    test(p: Person) {
        let modelState = arguments[arguments.length - 1];
        console.log(modelState);
        return;
    }
}

Result:

When @validated is used on a method, an object containing the validation results for each of the method arguments will be passed as the last argument. It can be retrieved either by explicitly adding a parameter to the method's signature or by indexing the arguments array. The indices in the modelState array correspond to the indices of the method's parameters - modelState[0] cotnains the validation errors for parameter p of the method test in the previous example.

[ [ { property: 'name', message: 'name is required.' },
    { property: 'age',
      message: 'age must be in the range [1, 10].' },
    { property: 'data', message: 'data must be of length 10.' },
    { property: 'data', message: 'data is required' },
    { property: 'sex', message: 'sex is required.' } ] ]