Reading

Reading — config.get

config.get(path: string, defaultValue?: any): any

Returns the value at path. Substitutes defaultValue for absent paths (or a path that terminates in undefined). A stored null is a present value and is returned as-is — see the gotchas.

Signatures

config.get("api.url");                       // -> any (null when missing — the default default)
config.get("api.url", "https://default");    // -> any
const timeout: number = config.get("api.timeout", 30000);

config.get is not a TypeScript generic — its return type is any. Narrow at the call site by annotating the receiving variable, asserting (config.get("api.url") as string), or wrapping (see mongez-config-typing).

Dot-notation

Paths are split on .. Each segment is a key into the value at the previous step:

config.set({
  api: {
    url: "https://api.example.com",
    headers: { "x-app-id": "web" },
  },
});

config.get("api.url");                       // "https://api.example.com"
config.get("api.headers.x-app-id");          // "web"

Numeric segments index arrays

config.set({ servers: ["primary", "secondary", "fallback"] });

config.get("servers.0");                     // "primary"
config.get("servers.2");                     // "fallback"
config.get("servers.5", "n/a");              // "n/a"

Default-substitution rules

defaultValue is returned ONLY when the path is missing or terminates in undefined. Other falsy values pass through:

Stored value	get(path, "fallback")
0	0
""	""
false	false
null	null
undefined	"fallback"
missing path	"fallback"

config.set("flag.enabled", false);
config.get("flag.enabled", true);            // false   (NOT true)

config.set("count", 0);
config.get("count", 1);                      // 0

config.set("name", "");
config.get("name", "Anonymous");             // ""

If you need “falsy → default” semantics, do it at the call site: config.get("flag", false) || true.

The default for defaultValue is null

config.get("never.set");                     // null (NOT undefined)

This is helpful for ?? patterns: const url = config.get("api.url") ?? "https://default".

Gotchas

• Dots in keys. If you stored a key with a literal dot ({"api.example.com": 1}), get("api.example.com") reads obj.api.example.com — three segments — and returns the default. Avoid dots inside keys.
• A stored null is a value, and the default does NOT replace it. config.set(k, null) then config.get(k, "x") returns null. That is deliberate: “configured to nothing” is a different statement from “not configured”. If you want the default back, clear the key with config.unset(k) or config.set(k, undefined) — both remove it (since 1.2.0). Before 1.2.0, set(k, undefined) wrote null and silently killed the fallback on every later read.
• Missing intermediate segments. config.get("a.b.c", "x") returns "x" if any of a, b, or c is missing — get short-circuits the moment it hits a missing key.