Synopsis
To simplify migration from LoopBack 3, LoopBack 4 provides a CLI tool to import LoopBack 3 models into your LoopBack 4 project.
Warning: This command is experimental and not feature-complete yet. See the list of known limitations below.
Overview
Import one or more models from your LB 3.x application by running
lb4 import-lb3-models command.
Arguments
lb3app: Path to the directory containing your LoopBack 3.x application.
Important:
The generator loads the application via require(), it does not
support applications that are unable to boot (throw errors at startup).
Options
outDir: Directory where to write the generated source file. Default:
src/models
Known limitations
Note:
Please up-vote the tracking GitHub issue for scenarios that are important to your project. It will help us to better prioritize which limitations to remove first.
Nested properties are not upgraded
The tracking GitHub issue: loopback-next#3811
When a property is defined with a complex object type, the nested property definitions are not converted from LB3 to LB4 format.
Workaround: Fix the generated definition manually.
Model relations are not imported
The tracking GitHub issue: loopback-next#3812
Workaround: define relational metadata & navigational properties manually.
MongoDB’s ObjectID type
The tracking GitHub issue: loopback-next#3814.
For models attached to MongoDB datasource, the imported LB4 model contains
incorrect definition of the primary key property of ObjectID type.
As a workaround, you can change the property definition from:
@property({
type: ObjectID;
})
id: ObjectID;
to:
@property({
type: 'string',
mongodb: {dataType: 'ObjectID'}
})
id: string;
Some settings cannot be imported
The following fields from model settings are not supported by LoopBack 4 and therefore ignored during import:
aclsmethodsmixinsvalidations