Struct serde_json::map::VacantEntry

pub struct VacantEntry<'a> { /* private fields */ }

A vacant Entry. It is part of the Entry enum.

Implementations

impl<'a> VacantEntry<'a>

pub fn key(&self) -> &String

Gets a reference to the key that would be used when inserting a value through the VacantEntry.

Examples

use serde_json::map::Entry;

let mut map = serde_json::Map::new();

match map.entry("serde") {
    Entry::Vacant(vacant) => {
        assert_eq!(vacant.key(), &"serde");
    }
    Entry::Occupied(_) => unimplemented!(),
}

Examples found in repository

src/map.rs (line 538)

    pub fn key(&self) -> &String {
        match self {
            Entry::Vacant(e) => e.key(),
            Entry::Occupied(e) => e.key(),
        }
    }

pub fn insert(self, value: Value) -> &'a mut Value

Sets the value of the entry with the VacantEntry’s key, and returns a mutable reference to it.

Examples

use serde_json::map::Entry;

let mut map = serde_json::Map::new();

match map.entry("serde") {
    Entry::Vacant(vacant) => {
        vacant.insert(json!("hoho"));
    }
    Entry::Occupied(_) => unimplemented!(),
}

Examples found in repository

src/map.rs (line 558)

    pub fn or_insert(self, default: Value) -> &'a mut Value {
        match self {
            Entry::Vacant(entry) => entry.insert(default),
            Entry::Occupied(entry) => entry.into_mut(),
        }
    }

    /// Ensures a value is in the entry by inserting the result of the default
    /// function if empty, and returns a mutable reference to the value in the
    /// entry.
    ///
    /// # Examples
    ///
    /// ```
    /// # use serde_json::json;
    /// #
    /// let mut map = serde_json::Map::new();
    /// map.entry("serde").or_insert_with(|| json!("hoho"));
    ///
    /// assert_eq!(map["serde"], "hoho".to_owned());
    /// ```
    pub fn or_insert_with<F>(self, default: F) -> &'a mut Value
    where
        F: FnOnce() -> Value,
    {
        match self {
            Entry::Vacant(entry) => entry.insert(default()),
            Entry::Occupied(entry) => entry.into_mut(),
        }
    }