EntityHelper and Decorated Entities

Updating entity values with IEntity.assign()

When you want to update entity based on user input, you will usually have just plain string ids of entity relations as user input. Normally you would need to use EntityManager.getReference() to create references from each id first, and then use those references to update entity relations:

const jon = new Author('Jon Snow', 'snow@wall.st');
const book = new Book('Book', jon);
book.author = orm.em.getReference<Author>(Author, '...id...');

Same result can be easily achieved with IEntity.assign():

book.assign({
title: 'Better Book 1',
author: '...id...',
});
console.log(book.title); // 'Better Book 1'
console.log(book.author); // instance of Author with id: '...id...'
console.log(book.author.id); // '...id...'

By default, IEntity.assign(data) behaves same way as Object.assign(entity, data), e.g. it does not merge things recursively. To enable deep merging of object properties, use second parameter to enable mergeObjects flag:

book.meta = { foo: 1, bar: 2 };
book.assign({ meta: { foo: 3 } }, { mergeObjects: true });
console.log(book.meta); // { foo: 3, bar: 2 }
book.assign({ meta: { foo: 4 } });
console.log(book.meta); // { foo: 4 }

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