Union & Literal Types — Direction & Status

Use literal types and union types to build a small routing helper.

Implement solve(direction, speed) where:

• direction is one of: "north" | "south" | "east" | "west"
• speed is one of: "slow" | "fast"
• Returns a string: "{direction} at {speed} speed"

Also implement isCardinal(direction) which returns true if the direction is one of the four cardinal directions, false otherwise.

Examples

• solve("north", "fast") → "north at fast speed"
• isCardinal("north") → true
• isCardinal("diagonal") → false