@chocolatesoup/joiful-dynamodb

@table('test-table')
class Model extends Entity {
}

const model = new Model({ attr1: '1', attr2: '2' });
model.create(); // This will create the record in the 'test-table' DynamoDB table.

Once the aliasTo decorator is set on an Entity Class model property, the instance, the setters and getters will be set and both variables will be linked.

class Model extends Entity {
   myProperty number;

   @aliasTo('myProperty')
   aliasProperty: number;
}

const model = new Model({
   aliasProperty: 1;
})

console.log(model.myProperty) // 1
console.log(model.aliasProperty) // 1

model.myProperty = 2;

console.log(model.myProperty) // 2
console.log(model.aliasProperty) // 2

model.aliasProperty = 3;

console.log(model.myProperty) // 3
console.log(model.aliasProperty) // 3

Once the aliases decorator is set on an Entity Class model property, the instance will have getters and setters of each of the aliases.

class Model extends Entity {
  @aliases(['alias1', 'alias2'])
  myProperty number;
}

const model = new Model({
  alias1: 1,
});

console.log(model.myProperty) // 1
console.log(model.alias1) // 1
console.log(model.alias2) // 1

model.myProperty = 2;

console.log(model.myProperty) // 2
console.log(model.alias1) // 2
console.log(model.alias2) // 2

model.alias2 = 3;

console.log(model.myProperty) // 3
console.log(model.alias1) // 3
console.log(model.alias2) // 3

class Model extends Entity {
  @compositeKey(['field1', 'field2'])
  compositeProperty: string;

  @prop()
  field1: string;

  @prop()
  field2: string;
}

const model = new Model({ field1: 'part1', field2: 'part2' });

console.log(model.compositeProperty) // undefined;
console.log(model.field1) // 'part1'
console.log(model.field2) // 'part2'

console.log(model.transformedAttributes) // { compositeProperty: 'part1#part2', field1: 'part1', field2: 'part2' }

• When the hasMany is set on the parent with a foreignKey AND indexName, automatically, when querying the child with related records, it will bring the parent record too.

import * as Joi from 'joi';

class ChildModel extends Entity {
  @prop()
  @validate(Joi.string().required())
  pk: string;

  @prop()
  sk: string;

  @prop()
  fk: string;
}

class ParentModel extends Entity {
  @prop({ primaryKey: true })
  pk: string;

  @hasMany(ChildModel, { nestedObject: false, required: true, foreignKey: 'fk', indexName: 'byFK' })
  children: ChildModel[];
}

const parent = new ParentModel({
  pk: '1',
});

console.log(parent.children) // []

console.log(parent.valid) // false # As children is set as required, it is invalid as it has no children now..

parent.children = [new ChildModel({
  pk: 'pk-from-child-1',
  sk: 'sk-from-child-1',
}), new ChildModel({
  sk: 'sk-from-child-2',
})]

console.log(parent.children[0].pk) // 'pk-from-child-1'
console.log(parent.children[0].sk) // 'sk-from-child-1'

console.log(parent.children[1].pk) // undefined
console.log(parent.children[1].sk) // 'sk-from-child-2'

console.log(parent.valid) // false # As the second child is invalid, parent is also invalid.

parent.children[1].pk = 'pk-from-child-2';

console.log(parent.children[1].pk) // 'pk-from-child-2'
console.log(parent.children[1].sk) // 'sk-from-child-2'

console.log(parent.transformedAttributes) // # The children attributes do not appear in the attributes because they will become new records.

console.log(parent.valid) // true # As now all children are valid, the parent is also valid.

parent.create() // This will insert 3 records in the database. The parent and each of the children. All of them will have fk column set to 'ParentModel-1'

• Besides validations and setting the child instance, it also creates getters and setters for all child instances in the parent. Look example for more details.
• When the hasOne is set on the parent with a foreignKey AND indexName, automatically, when querying the child with related records, it will bring the parent record too.

import * as Joi from 'joi';

class ChildModel extends Entity {
  @prop()
  @validate(Joi.string().required())
  pk: string;

  @prop()
  sk: string;

  @prop()
  fk: string;
}

class ParentModel extends Entity {
  @prop({ primaryKey: true })
  pk: string;

  @hasOne(ChildModel, { nestedObject: true, required: true })
  child1: ChildModel;

  @hasOne(ChildModel, { nestedObject: false, required: false, foreignKey: 'fk' })
  child2: ChildModel;
}

const parent = new ParentModel({
  pk: '1',
  child1: {
    pk: 'pk-from-child-1',
    sk: 'sk-from-child-1',
  },
  child2Sk: 'sk-from-child-2',
});

console.log(parent.child1.pk) // 'pk-from-child-1'
console.log(parent.child1.sk) // 'sk-from-child-1'
console.log(parent.child1Pk) // 'pk-from-child-1'
console.log(parent.child1Sk) // 'sk-from-child-1'

console.log(parent.child2.pk) // undefined
console.log(parent.child2.sk) // 'sk-from-child-2'
console.log(parent.child2Pk) // undefined
console.log(parent.child2Sk) // 'sk-from-child-2'

parent.child2.pk = 'pk-from-child-2';

console.log(parent.child2.pk) // 'pk-from-child-2'
console.log(parent.child2.sk) // 'sk-from-child-2'
console.log(parent.child2Pk) // 'pk-from-child-2'
console.log(parent.child2Sk) // 'sk-from-child-2'

console.log(parent.transformedAttributes) // { child1: { pk: 'pk-from-child-1', sk: 'sk-from-child-1' } } # The child2 does not appear in the attributes because it will become a new record.

console.log(parent.valid) // false # As child 2 is invalid, parent is invalid also.

model.child2 = undefined;

console.log(parent.valid) // true # As child 2 is not required, parent is valid.

model.child1 = undefined;

console.log(parent.valid) // false # As child 1 is required, the parent is invalid.

parent.create() // This will insert 2 records in the database. The parent and the child 2. Both will have the property fk set to 'ParentModel-1'

class Model extends Entity {
  @prop({ primaryKey: true })
  property1: string;

  @prop({ secondaryKey: true })
  property2: string;

  @prop({ createdAt: true })
  cAt: string;

  @prop({ updatedAt: true })
  uAt: string;
}

const model = new Model({
  property1: '1',
  property2: '2',
  cAt: '3',
  uAt: '4',
  extraAttribute: '5',
});

console.log(model.property1) // '1'
console.log(model.property2) // '2'
console.log(model.cAt) // '3'
console.log(model.uAt) // '4'
console.log(model.extraAttribute) // '5'

model.property1 = 'changed1';
console.log(model.property1) // 'changed1';

model.property2 = 'changed2';
console.log(model.property2) // 'changed2';

model.cAt = 'changed3';
console.log(model.cAt) // 'changed3';

model.uAt = 'changed4';
console.log(model.uAt) // 'changed4';

model.extraAttribute = 'changed5';
console.log(model.extraAttribute) // 'changed5';

model.extraAttribute2 = 'changed6'; // ERROR: the setter does not exist!

console.log(model._primaryKey) // 'property1';
console.log(model._secondaryKey) // 'property2';
console.log(model._createdAtKey) // 'cAt';
console.log(model._updatedAtKey) // 'uAt';

model.create(); // In the database it will be saved like this: { property1: 'Model-changed1', property2: 'Model-changed2', cAt: '2022-02-07T16:16:44.975Z', uAt: '2022-02-07T16:16:44.975Z', extraAttribute: 'changed5' };

If you are setting the decorated Entity it NEEDS to be of Joi.object() type. Remember that if you set a new validation object in the Entitiy itself you need to add the .unknown(true) if you want to accept any attribute.

import * as Joi from 'joi';

@validate(Joi.object().unknown(true).and('attribute1', 'attribute2'))
class Model extends Entity {
  @validate(Joi.string().required().trim())
  pk: string;

  @validate(Joi.string().trim())
  sk: string;

  @validate(Joi.string())
  attribute1: string;

  @validate(Joi.string())
  attribute2: string;
}

const model = new Model({ pk: '1' });

console.log(model.valid) // true

model.sk = '2'
console.log(model.valid) // true

model.pk = undefined;
console.log(model.valid) // false

model.pk = '   1 2   ';
console.log(model.validatedAttributes) // { pk: '1 2', sk: '2' } # The joi transfromation happens when validating but doesn't change the original attributes. But the transformed attributes are the ones used on save.

model.attribute1 = '1'
console.log(model.valid) // false # It is invalid because of the entity level validation with the Joi.object().and()

model.attribute2 = '2'
console.log(model.valid) // true # It is now valid because it passes the Joi.object().and() validation.