Array

Creates a schema to normalize an array of schemas. If the input value is an Object instead of an Array, the normalized result will be an Array of the Object's values.

Note: The same behavior can be defined with shorthand syntax: [ mySchema ]

• definition: required A singular schema that this array contains or a mapping of schema to attribute values.
• schemaAttribute: optional (required if definition is not a singular schema) The attribute on each entity found that defines what schema, per the definition mapping, to use when normalizing. Can be a string or a function. If given a function, accepts the following arguments: value: The input value of the entity. parent: The parent object of the input array. * key: The key at which the input array appears on the parent object.

Instance Methods

• define(definition): When used, the definition passed in will be merged with the original definition passed to the Array constructor. This method tends to be useful for creating circular references in schema.

Usage

To describe a simple array of a singular entity type:

const data = [
  { id: '123', name: 'Jim' },
  { id: '456', name: 'Jane' },
];
class User extends Entity {
  readonly name: string = '';
  pk() {
    return this.id;
  }
}

const userListSchema = new schema.Array(User);
// or use shorthand syntax:
const userListSchema = [User];

const normalizedData = normalize(data, userListSchema);

const data = [
  { id: '123', name: 'Jim' },
  { id: '456', name: 'Jane' },
];
class User extends Entity {
  pk() {
    return this.id;
  }
}

const userListSchema = new schema.Array(User);
// or use shorthand syntax:
const userListSchema = [User];

const normalizedData = normalize(data, userListSchema);

Output

{
  entities: {
    User: {
      '123': { id: '123', name: 'Jim' },
      '456': { id: '456', name: 'Jane' }
    }
  },
  result: [ '123', '456' ]
}

Dynamic entity types

If your input data is an array of more than one type of entity, it is necessary to define a schema mapping.

Note: If your data returns an object that you did not provide a mapping for, the original object will be returned in the result and an entity will not be created.

string schemaAttribute

const data = [
  { id: 1, type: 'admin' },
  { id: 2, type: 'user' },
];

class User extends Entity {
  readonly type = 'user' as const;
  pk() {
    return this.id;
  }
}
class Admin extends Entity {
  readonly type = 'admin' as const;
  pk() {
    return this.id;
  }
}
const myArray = new schema.Array(
  {
    admin: Admin,
    user: User,
  },
  'type'
);

const normalizedData = normalize(data, myArray);

function schemaAttribute

The return values should match a key in the definition. Here we'll show the same behavior as the 'string' case, except we'll append an 's'.

const data = [
  { id: 1, type: 'admin' },
  { id: 2, type: 'user' },
];

class User extends Entity {
  readonly type = 'user' as const;
  pk() {
    return this.id;
  }
}
class Admin extends Entity {
  readonly type = 'admin' as const;
  pk() {
    return this.id;
  }
}
const myArray = new schema.Array(
  {
    admins: Admin,
    users: User,
  },
  (input, parent, key) => `${input.type}s`,
);

const normalizedData = normalize(data, myArray);

const data = [{ id: 1, type: 'admin' }, { id: 2, type: 'user' }];

class User extends Entity {
  pk() {
    return this.id;
  }
}
class Admin extends Entity {
  pk() {
    return this.id;
  }
}
const myArray = new schema.Array(
  {
    admins: Admin,
    users: User,
  },
  (input, parent, key) => `${input.type}s`,
);

const normalizedData = normalize(data, myArray);

Output

{
  entities: {
    Admin: { '1': { id: 1, type: 'admin' } },
    User: { '2': { id: 2, type: 'user' } }
  },
  result: [
    { id: 1, schema: 'Admin' },
    { id: 2, schema: 'User' }
  ]
}