ts-model-validators

Typescript(ts) Model Validator

this module helps build validation rules for models in typescript projects.

Installation & Usage

Install module:

npm i --save ts-model-validators

or

npm i --save @dodo-micro/ts-model-validators

Create your class and put some validation decorators on its properties you want to validate:

// some imports 
// ...
export class Education {

    @min(12, 'participation count must be equal or greater than {0}')
    public participationCount = 0;

    @min(10, 'custom msg without arg')
    public customField = 0;
}

Execute the validation and get error messages:

// some imports 
// ...
const education = new Education();
const validation: ValidationMessage[] = validatorService.validate(education);

/**
 * the structure of a validation Message:
    class ValidationMessage {
        name: string = "";
        msgs: string[] = [];
    }
 * /

Built-in rules

With error message template, {i} will be replaced by i-th passed parameter.

Decorator	Parameter	Data type
required	error template	any
requiredIf	the property name that if it has value current field is required. error template	any
afterOrEqualTo	the other field's name to compare. error template	string
beforeOrEqualTo	the other field's name to compare. error template	string
dateFormat	error template	string
min	min value. error template	number
max	max value. error template	number
minLength	min value . error template	string
maxLength	max value . error template	string
email	error template	string

Update version 1.2.x

Decorator	Parameter	Data type
contains	value that you want to check, error template	array
existsIn	array input, error template	any
notIn	array input, error template	any
intersect	array input, error template	array

Create custom a validation rule

Beside built-in rules, we can easily create custom validation rule as a Decorator with ValidatorFactory:

// some imports 
// ...
export function min(minValue: number, errorTemplate: string) {
    const rule = new Rule<number>(errorTemplate, [minValue]);

    // the method check the validity of data, the second argument of this method can be the target object (check the rule beforeOrEqualTo)
    rule.isValid = function (input: number): boolean {
        return input >= this.msgArgs[0];
    }

    return validatorFactory.build(rule);
}


export function beforeOrEqualTo(anotherKey: string, errorTemplate: string) {
    const rule = new Rule<string>(errorTemplate, [anotherKey]);
    rule.isValid = function (input: string, entity: any): boolean {
        const anotherField = entity[anotherKey];
        const target = input;
        
        // ... 
        // Your implementations...
        // ...
        //   
    }

    return validatorFactory.build(rule);
}

Update version 1.2.x

Introduce new class CreateValidatorFactory to reduce complexity of decorator factories, usage:

// some imports 
// ...

export function contains(element: string, errorTemplate: string) {
    return new CreateValidatorFactory<Array<string>>(errorTemplate)
        .arguments([element])
        .validateFunction((input) => input.includes(element))
        .build();
}

Todos

• [ ] improve usability of module