Pattern Properties

Regex patterns map directly to TypeScript template literals — ^user_ becomes `user_${string}` — giving type-safe dynamic keys with no extra work.

Basic pattern properties


const configSchema = new SchemaBuilder()
  .object()
  .properties({ appName: (s) => s.string() })
  .patternProperties({
    "^env_": (s) => s.string(), // properties starting with "env_"
    "^feature_": (s) => s.boolean(), // properties starting with "feature_"
    "_id$": (s) => s.number(), // properties ending with "_id"
  })
  .required(["appName"])
  .build();
 
type Config = Jet.Infer<typeof configSchema>;
// {
//   appName: string;
//   [key: `env_${string}`]: string;
//   [key: `feature_${string}`]: boolean;
//   [key: `${string}_id`]: number;
// }

Supported pattern types


// Prefix with separator
"^data_"   → `data_${string}`
"^api-"    → `api-${string}`
"^config." → `config.${string}`
 
// Prefix without separator
"^user"    → `user${string}`
 
// Suffix with separator
"_id$"     → `${string}_id`
"-name$"   → `${string}-name`
".json$"   → `${string}.json`
 
// Suffix without separator
"Type$"    → `${string}Type`
 
// Infix (contains separator)
"_"        → `${string}_${string}`
"-"        → `${string}-${string}`
"."        → `${string}.${string}`
 
// Wildcards and complex patterns fall back to string
".*"          → string
"^[a-zA-Z].*" → string
".*[0-9]$"    → string

Complex regex like ^[a-z]{3,5}$ or \d+ fall back to string. Only common, simple patterns convert to template literals.