SvelteKit superforms in SSG mode gives typescript error for data.form. Where my `form`?

SvelteKit superforms in SSG mode gives TypeScript error for data.form. Where’s my `form`?

If you’re using SvelteKit with superforms in SSG (Static Site Generation) mode, you may have encountered a TypeScript error related to accessing the `form` property on your data object. This error occurs because the Svelte compiler is unable to infer the type of the `form` property when using SSG.

Fortunately, there are a couple of solutions to this problem.

Solution 1: Type Assertion

The first solution involves using a type assertion to explicitly tell TypeScript the type of the `form` property. This can be done by using the `as` keyword followed by the desired type.

    // Assuming your data object looks like this
    let data = {
        form: {
            // form properties
        }
    };
    
    // Type assertion
    let form = data.form as YourFormType;
    

Replace `YourFormType` with the actual type of your form object. This will inform TypeScript about the type of the `form` property and resolve the error.

Solution 2: Optional Chaining

The second solution involves using optional chaining to access the `form` property. Optional chaining allows you to safely access nested properties even if they are potentially undefined.

    // Assuming your data object looks like this
    let data = {
        form: {
            // form properties
        }
    };
    
    // Optional chaining
    let form = data.form?.yourProperty;
    

In this example, replace `yourProperty` with the actual property you want to access from the `form` object. The optional chaining operator (`?.`) will ensure that the code doesn’t throw an error if the `form` property is undefined.

Conclusion

By using either type assertion or optional chaining, you can resolve the TypeScript error related to accessing the `form` property in SvelteKit superforms while in SSG mode. Choose the solution that best fits your use case and enjoy a smooth development experience with TypeScript and SvelteKit!