angular/aio/content/errors/NG0209.md

@name Invalid multi provider @category runtime @shortDescription Expected provider to be multi: true but did not get an Array

@description

The Angular runtime will throw this error when it injects a token intended to be used with multi: true but a non-Array was found instead. For example, ENVIRONMENT_INITIALIZER should be provided like {provide: ENVIRONMENT_INITIALIZER, multi: true, useValue: () => {...}}.

@reviewed 2022-11-28