Obj-schema-validator

Intalling

Using npm:

$ npm install obj-schema-validator

Once the package is installed, you can import the library using the import or require approach:

import { DtoSchema, Schema } from "obj-schema-validator";

Later you must define a schema for the use of a dto, this by declaring a class that extends the DtoSchema class, you must implement the schema attribute of type Schema.

class UserDto extends DtoSchema {
    schema: Schema = {
        name: {
            required: true,
            type: "string",
            options: {
                toTitleCase: true,
            }
        },
        age: {
            required: false,
            type: "number",
        },
        city: {
            required: true,
            type: "string",
            options: {
                includes:  ["CDMX", "Queretaro"]
            }
        }

    };

}

The schema attribute is a hashmap where each key is an object in which it is declared whether it is required, the type, and as optional values ​​its initial value and an options object.

schema: Schema = {
        name: {
            required: true,
            type: "string",
            options: {
                toTitleCase: true,
            }
        },
        email: {
            required: true,
            type: "string",
            options: {
                toLowerCase: true,
                isEmail: true,
            }
        },
        age: {
            required: false,
            type: "number",
            options: {
                minimunValue: 5
            }
        },
        city: {
            required: true,
            type: "string",
            options: {
                includes: ["Mexico", "Queretaro"] // indicate the list of allowed values 

            }
        },
    };

The options object has these optional values

type options = {
    toTitleCase: boolean, 
    // Converts the string to "Title Case", that is, capitalizes the first letter of each word and lowercases the rest.

    toUpperCase: boolean,
    // Converts the entire string to uppercase.

    toLowerCase: boolean,
    // Converts the entire string to lowercase
    
    isEmail: boolean,
    // Checks if the string is a valid email using a standard regular expression for validating emails

    includes: Array<any>,
    // Checks if the string is within the array of provided values.

    checkPattern: RegExp,
    // Check if the string matches the provided pattern (regular expression).
    
    isLength: number,
    // Checks if the length of the string is exactly equal to the provided number.
    
    minLength: number,
    // Checks if the length of the string is greater than or equal to the provided number.

    maxLength: number,
    // Checks if the length of the string is less than or equal to the provided number.

    minimunValue: number,
    // Checks if the numeric value of the string is greater than or equal to the provided number.
        
    maximunValue: number,
    // Checks if the numeric value of the string is less than or equal to the provided number.
}

You can use the create method of your dto to carry out the validations, this method returns an array with two positions, the first being the error and the second being the values ​​already validated.

const data = {
    name: "test lastname",
    age: "5",
    email: "[email protected]",
    password: "test",
    city: "CDMX",
}

const [error, result] = new UserDto().create(data);