[Solved] Typescript: Generic type 'ɵɵDirectiveDeclaration' requires 6 type argument(s)

TypeScript error, TS2314, which states that a generic type 'ɵɵDirectiveDeclaration' requires 6 type argument(s), error often occurs when working with Angular directives.

let's first understand what the error is indicating. The 'ɵɵDirectiveDeclaration' is an Angular API for declaring directives. Angular directives typically require multiple type arguments to properly define their behavior.

As we can see the error suggests that we're not providing all the required type arguments when using 'ɵɵDirectiveDeclaration', if we're missing some type parameters in our directive declaration.

            import { Directive } from '@angular/core';
            
            // Define a custom directive
            @Directive({
                selector: '[appCustomDirective]'
            })
            export class CustomDirective {
                // Implement directive logic here
            }
        
    

In the above code , we've defined a custom directive named 'CustomDirective'. However, if this directive needs to use the 'ɵɵDirectiveDeclaration' API, we must ensure that all required type arguments are provided.

For example, if our directive requires specific type arguments for its functionality, we need to include them in the directive declaration:

import { Directive } from '@angular/core';
            
            // Define a custom directive with type arguments
            @Directive({
                selector: '[appCustomDirective]',
                // Provide all required type arguments
                // For example, if the directive requires 6 type arguments, ensure to provide them all
                // Example:
                // ɵɵDirectiveDeclaration<CustomDirective, 'appCustomDirective', never, {}, {}, {}>
            })
            export class CustomDirective {
                // Implement directive logic here
            }

We encountered the same issue. Our best solution either go with ngrx/component 14.3.0 if we're using Angular 14, or update directly to Angular 15.

Regarding this solution, it's essential to consider the compatibility and stability of our Angular application. If we're currently on Angular 14 and facing issues, upgrading to ngrx/component 14.3.0 might provide the necessary fixes. 

On the other hand, updating directly to Angular 15 could also be a good solution if our project allows for it. Angular 15 might come with its own set of improvements and bug fixes that could resolve the issue more comprehensively.