AWS CDK error TS7009: 'new' expression, whose target lacks a construct signature, implicitly has an 'any' type. when importing a resource

17 May 2021 — Written by Edwin

error TS7009: 'new' expression, whose target lacks a construct signature, implicitly has an 'any' type.

This might be a simple one and still, it took me some time to realise what's up here. In my case I was importing an existing Loadbalancer into my CDK app:

const lb = new ApplicationLoadBalancer.fromApplicationLoadBalancerAttributes(this, 'ALB', {
  loadBalancerArn: ssm.StringParameter.valueForStringParameter(this, '/APP/AlbArn'),
  securityGroupId: SECURITY_GROUP_ID
});

The solution is as simple as it gets, its not a new resource but importing an existing resource. So instead of defining the loadbalancer as a new resources with:

const lb = new ApplicationLoadBalancer....

Just remove the new and you should be good to go.

const lb = ApplicationLoadBalancer.fromApplicationLoadBalancerAttributes(this, 'ALB', {
  loadBalancerArn: ssm.StringParameter.valueForStringParameter(this, '/APP/AlbArn'),
  securityGroupId: SECURITY_GROUP_ID
});

Hope that helps! If not, a great place to ask for help is the CDK.dev slack channel. A huge community that will gladly try to help you with your specific problem.