Comparisons & logic

• == != < <= > >= : compare two values, produce a boolean
• && : logical AND — both operands must be boolean
• || : logical OR — both operands must be boolean
• ! : boolean negation
• Playground

Operator	Effect
== != < <= > >=	compare two values, produce a boolean
&&	logical AND — both operands must be boolean
[`
!	boolean negation

== != < <= > >= : compare two values, produce a boolean

Comparing values whose types have no overlap — a number against a string, say — can never be true. The compiler warns (TF2367) instead of letting the mapping silently return false forever. Remove the mismatched literal to fix it — it is a warning, not an error, so the mapping still runs.

isAdult: user.age >= 18
isAdmin: user.role == "admin"
passed: user.score > 50

&& : logical AND — both operands must be boolean

&&, ||, and ! require boolean operands — no truthiness on strings or numbers. user.active && user.age is rejected (TF2004) since age is not boolean.

canPost: user.active && user.verified

|| : logical OR — both operands must be boolean

needsReview: !user.verified || user.age < 16

! : boolean negation

blocked: !user.verified

Playground

Mapping✔Playground ↗

input user: { active: boolean, verified: boolean, age: number }

map {
  canPost: user.active && user.verified,
  needsReview: !user.verified || user.age < 16,
}

input user: { active: boolean, verified: boolean, age: number } map { canPost: user.active && user.verified, needsReview: !user.verified || user.age < 16, }

Input JSON

{ "active": true, "verified": false, "age": 15 }

{ "active": true, "verified": false, "age": 15 }

Output

{
  "canPost": false,
  "needsReview": true
}

inferred type{ canPost: boolean; needsReview: boolean }

Next: Conditionals.