Quick Start

ObjectParser is designed to guarantee the structure of the target object according to a certain scheme. This means that the parser will return an object with the properties specified in the schema. which:

Will be of the specified type.
Will be checked for existence.
Will be checked by a custom validator.
Will have default values in case of absence.

Here is a example:

javascript

const schema = parser.schema({
  name: String,
  age: [String, Number],
  role: parser.property({
    type: String,
    required: false,
    default: 'anonymous',
    validator: (value) => {
      if (!['anonymous', 'user', 'admin'].includes(value))
        throw new Error('Role must be "anonymous", "user" or "admin".')
      return true
    },
  }),
})

const target = {
  name: 'Dmitry',
  age: 19,
}

parser.parse(target, schema)
// => {
//   value: { name: 'Dmitry', age: 19, role: 'anonymous' }
//   errors: []
// }

What's going on here:

Created the object schema where:
- name - is required property which can be only String.
- age - is required property which can be String or Number.
- role - is not required property, which can be only an "anonymous", "user" or "admin" string. Value by default: "anonymous".
Parsed the target object by the object schema.

The result of parsing is an object, where:

value - parsed object. By default is a reference on the original object.
errors - an array of GeneralError.

Error handling

If errors occur during parsing, they will be in errors, and the property itself will not be changed.

Example:

javascript

const schema = parser.schema({
  name: String,
  age: [String, Number],
  role: parser.property({
    type: String,
    required: true,
    validator: (value) => {
      if (!['anonymous', 'user', 'admin'].includes(value))
        throw new Error('Role must be "anonymous", "user" or "admin".')
      return true
    },
  }),
})

parser.parse({ age: false, role: 'hello' }, schema)
// => {
//   value: { age: false, role: 'hello' },
//   errors: [
//     {
//       key: 'name',
//       error: {
//         name: 'PropertyError',
//         message: 'The property not exists in the object.',
//         exists: false,
//         value: undefined,
//         valueIsDefault: false,
//         valueConstructors: [],
//         schema: (a reference to a property schema)
//       }
//     },
//     {
//       key: 'age',
//       error: {
//         name: 'PropertyError',
//         message: 'The property has an invalid type.',
//         exists: true,
//         value: false,
//         valueIsDefault: false,
//         valueConstructors: [ [Function: Boolean], [Function: Object] ],
//         schema: (a reference to a property schema)
//       }
//     },
//     {
//       key: 'role',
//       error: {
//         name: 'PropertyError',
//         message: 'Role must be "anonymous", "user" or "admin".',
//         exists: true,
//         value: 'hello',
//         valueIsDefault: false,
//         valueConstructors: [ [Function: String], [Function: Object] ],
//         schema: (a reference to a property schema)
//       }
//     }
//   ],
// }

Note

The example above shows only a part of the possible errors that can occur during parsing. For more information about parsing see .single() or about an error see PropertyError.

Quick Start ​

Error handling ​

Quick Start

Error handling