Config Gatekeeper

Data from outside your program (a file, a request, a form) arrives as unknown. Write parseConfig(input: unknown): Result that checks it before anything trusts it.

A valid config is an object with:

host: a non-empty string
port: a whole number from 1 to 65535
debug: an optional boolean that defaults to false

Return { ok: true, value: { host, port, debug } } (only those three keys) when it is valid. Otherwise return { ok: false, error } with the first problem found, checking in this order: "config must be an object", "host must be a non-empty string", "port must be a whole number from 1 to 65535", "debug must be a boolean".

Examples

parseConfig({ host: "sky.local", port: 8080 })

→ { ok: true, value: { host: "sky.local", port: 8080, debug: false } }

parseConfig({ host: "a", port: 1, debug: true, secret: "x" })

→ { ok: true, value: { host: "a", port: 1, debug: true } }

solution.ts

TYPESCRIPT

Saved as you type

Tests

0 of 8 passing

•
valid, debug defaults
parseConfig({ host: "sky.local", port: 8080 })
expected { ok: true, value: { host: "sky.local", port: 8080, debug: false } }
•
extra keys are dropped
parseConfig({ host: "a", port: 1, debug: true, secret: "x" })
expected { ok: true, value: { host: "a", port: 1, debug: true } }
•
not an object
parseConfig("localhost:80")
expected { ok: false, error: "config must be an object" }
•
null is not a config
parseConfig(null)
expected { ok: false, error: "config must be an object" }
•
empty host
parseConfig({ host: "", port: 80 })
expected { ok: false, error: "host must be a non-empty string" }
•
port out of range
parseConfig({ host: "a", port: 70000 })
expected { ok: false, error: "port must be a whole number from 1 to 65535" }
•
port as text
parseConfig({ host: "a", port: "80" })
expected { ok: false, error: "port must be a whole number from 1 to 65535" }
•
debug as text
parseConfig({ host: "a", port: 80, debug: "yes" })
expected { ok: false, error: "debug must be a boolean" }

On the line

+80 XP

Pass all 8 tests to claim it.