1. napi_status napi_typeof(napi_env env, napi_value value, napi_valuetype* result)
    • [in] env: The environment that the API is invoked under.
    • [in] value: The JavaScript value whose type to query.
    • [out] result: The type of the JavaScript value.

    Returns napi_ok if the API succeeded.

    • napi_invalid_arg if the type of value is not a known ECMAScript type and value is not an External value.

    This API represents behavior similar to invoking the typeof Operator on the object as defined in [Section 12.5.5][] of the ECMAScript Language Specification. However, there are some differences:

    1. It has support for detecting an External value.
    2. It detects null as a separate type, while ECMAScript typeof would detect object.

    If value has a type that is invalid, an error is returned.