Type Annotations

Function parameters MUST have explicit type annotations.

Function return types MUST be explicitly declared.

Local variables SHOULD use type inference where the type is obvious.

Example (Correct):

// Explicit parameter and return types
function calculateDiscount(price: number, percent: number): number {
    return price * (1 - percent / 100)
}

// Type inference for obvious cases
const discount = calculateDiscount(100, 20)

Example (Incorrect):

// Missing return type
function calculateDiscount(price: number, percent: number) {
    return price * (1 - percent / 100)
}

// Unnecessary type annotation
const discount: number = calculateDiscount(100, 20)