lib.rs:

Helpers for dealing with Options/Results of collections or other things (like Strings) that may be empty.

Examples

Always start by including the traits:

use optempty::*;

These examples only show Vec<T>, but they support any type that implements IsEmpty.

empty_into_none

Some with an empty Vec becomes None.

use optempty::*;

let some: Option<Vec<&str>> = Some(vec![]);
let none = some.empty_into_none();
assert_eq!(None, none);

Some with a non-empty Vec remains unchanged.

#
let some = Some(vec!["a", "b", "c"]);
let still_some = some.clone().empty_into_none();
assert_eq!(some, still_some);

None remains unchanged.

#
let none: Option<Vec<&str>> = None;
let still_none = none.empty_into_none();
assert_eq!(None, still_none);

empty_into_err

Ok with an empty Vec becomes Err.

use optempty::*;

let ok: Result<Vec<&str>, &str> = Ok(vec![]);
let err = ok.empty_into_err(|| "was empty");
assert_eq!(Err("was empty"), err);

Ok with a non-empty Vec remains unchanged.

#
let ok = Ok(vec!["a", "b", "c"]);
let still_ok = ok.empty_into_err(|| "was empty");
assert_eq!(Ok(vec!["a", "b", "c"]), still_ok);

Err remains unchanged.

#
let err: Result<Vec<&str>, &str> = Err("failed");
let still_err = err.empty_into_err(|| "was empty");
assert_eq!(Err("failed"), still_err);

See more examples at:

• IsEmpty
• EmptyIntoNone
• EmptyIntoErr

Features

Available features are:

• querymap
  • Adds support for query_map::QueryMap
• serdejson
  • Adds support for serde_json::Map
• std
  • Adds support for types in std::collections in addition to types from alloc.

Default features:

• std