vendix-validation

rzyfront/vendix-validation

Coding

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Global validation is configured in apps/backend/src/main.ts with Nest ValidationPipe:

Design APIs assuming DTO validation runs before controller methods.

Use class-validator decorators for shape, required fields, enums, lengths, arrays, and numeric bounds.
Use class-transformer for type conversion: @Type(() => Number), nested DTOs, arrays, and targeted @Transform().
Prefer DTO validation for request structure and simple constraints.
Keep business invariants in services after resource lookup and permission/context checks.
Avoid hypothetical shared helpers unless they exist in the codebase.

Example patterns used in Vendix:

@IsOptional()
@Type(() => Number)
@IsInt()
store_id?: number;

@ValidateNested({ each: true })
@Type(() => LineItemDto)
items: LineItemDto[];

Use early returns/throws, but do not duplicate DTO validation unnecessarily:

Use VendixHttpException and domain error codes where available.

Use Angular reactive forms.
Use typed controls/getters when templates need strict FormControl bindings.
Use built-in Validators for simple fields and custom validators for cross-field rules.
Product pricing has real cross-field validators in the product module; prefer existing validators over new ad-hoc checks.
On submit, mark controls touched and return early when invalid.

Global validation is configured in apps/backend/src/main.ts with Nest ValidationPipe:

Design APIs assuming DTO validation runs before controller methods.

Use class-validator decorators for shape, required fields, enums, lengths, arrays, and numeric bounds.
Use class-transformer for type conversion: @Type(() => Number), nested DTOs, arrays, and targeted @Transform().
Prefer DTO validation for request structure and simple constraints.
Keep business invariants in services after resource lookup and permission/context checks.
Avoid hypothetical shared helpers unless they exist in the codebase.

Example patterns used in Vendix:

@IsOptional()
@Type(() => Number)
@IsInt()
store_id?: number;

@ValidateNested({ each: true })
@Type(() => LineItemDto)
items: LineItemDto[];

Use early returns/throws, but do not duplicate DTO validation unnecessarily:

Use VendixHttpException and domain error codes where available.

Use Angular reactive forms.
Use typed controls/getters when templates need strict FormControl bindings.
Use built-in Validators for simple fields and custom validators for cross-field rules.
Product pricing has real cross-field validators in the product module; prefer existing validators over new ad-hoc checks.
On submit, mark controls touched and return early when invalid.