Mostly the latter. With strict type checking enabled TsLint will warn you about impossible conditionals. You can go a step farther and force conditionals to ret

Mostly the latter. With strict type checking enabled TsLint will warn you about impossible conditionals. You can go a step farther and force conditionals to return boolean true/false. This disables JavaScript's "truth/falsey" but prevents a whole class of errors caused by questionable design decisions... Like empty arrays being truthy.