config/doc/quick-start.md

Quick start

Use Go 1.27.1 and TOML tags. Register defaults before loading sources:

cfg := config.New()
if err := cfg.Register("server.port", uint16(8080)); err != nil { return err }
if err := cfg.LoadFile("config.toml"); err != nil { return err }
if err := cfg.LoadEnv("APP_"); err != nil { return err }
if err := cfg.LoadCLI(os.Args[1:]); err != nil { return err }
port, err := config.GetTyped[uint16](cfg, "server.port")

APP_SERVER_PORT=9000 and --server.port=9001 address the same registered path. CLI has highest default priority. TOML values can be configured in a table:

[server]
port = 8080

For a typed application, use NewBuilder().WithTarget(&settings) as shown in the README. Build fills the supplied target once. Use AsStruct to obtain new snapshots after updates; retaining an old snapshot is safe.

A missing file returns ErrConfigNotFound along with a usable Config when all other initialization succeeds. Check that category explicitly if a file is optional. Invalid environment or CLI values remain fatal even when the file is missing. MustBuild and MustQuick ignore only a missing file and panic on other initialization errors. All source loads replace the previous values of that source.