feat: support to install the latest version

src/commands/install.rs

@@ -18,25 +18,33 @@ pub struct Install {
     pub version: Option<UserVersion>,
 
     /// Install latest LTS
-    #[clap(long, conflicts_with = "version")]
+    #[clap(long, conflicts_with_all = &["version", "latest"])]
     pub lts: bool,
+
+    /// Install latest version
+    #[clap(long, conflicts_with_all = &["version", "lts"])]
+    pub latest: bool,
 }
 
 impl Install {
     fn version(self) -> Result<Option<UserVersion>, Error> {
         match self {
-            Self {
-                version: Some(_),
-                lts: true,
-            } => Err(Error::TooManyVersionsProvided),
             Self {
                 version: v,
                 lts: false,
+                latest: false,
             } => Ok(v),
             Self {
                 version: None,
                 lts: true,
+                latest: false,
             } => Ok(Some(UserVersion::Full(Version::Lts(LtsType::Latest)))),
+            Self {
+                version: None,
+                lts: false,
+                latest: true,
+            } => Ok(Some(UserVersion::Full(Version::Latest))),
+            _ => Err(Error::TooManyVersionsProvided),
         }
     }
 }
@@ -74,6 +82,20 @@ impl super::command::Command for Install {
                 );
                 picked_version
             }
+            UserVersion::Full(Version::Latest) => {
+                let available_versions: Vec<_> = remote_node_index::list(&config.node_dist_mirror)
+                    .map_err(|source| Error::CantListRemoteVersions { source })?;
+                let picked_version = available_versions.last()
+                    .ok_or_else(|| Error::CantFindLatest)?
+                    .version
+                    .clone();
+                debug!(
+                    "Resolved {} into Node version {}",
+                    Version::Latest.v_str().cyan(),
+                    picked_version.v_str().cyan()
+                );
+                picked_version
+            }
             current_version => {
                 let available_versions: Vec<_> = remote_node_index::list(&config.node_dist_mirror)
                     .map_err(|source| Error::CantListRemoteVersions { source })?
@@ -153,6 +175,8 @@ pub enum Error {
     CantFindNodeVersion { requested_version: UserVersion },
     #[error("Can't find relevant LTS named {}", lts_type)]
     CantFindRelevantLts { lts_type: crate::lts::LtsType },
+    #[error("Can't find latest version")]
+    CantFindLatest,
     #[error("The requested version is not installable: {}", version.v_str())]
     UninstallableVersion { version: Version },
     #[error("Too many versions provided. Please don't use --lts with a version string.")]
@@ -175,6 +199,7 @@ mod tests {
         Install {
             version: UserVersion::from_str("12.0.0").ok(),
             lts: false,
+            latest: false,
         }
         .apply(&config)
         .expect("Can't install");

src/user_version.rs

@@ -41,7 +41,7 @@ impl UserVersion {
                     }
                 }
             }
-            (_, Version::Bypassed | Version::Lts(_) | Version::Alias(_)) => false,
+            (_, Version::Bypassed | Version::Lts(_) | Version::Alias(_) | Version::Latest) => false,
             (Self::OnlyMajor(major), Version::Semver(other)) => *major == other.major,
             (Self::MajorMinor(major, minor), Version::Semver(other)) => {
                 *major == other.major && *minor == other.minor

src/version.rs

@@ -9,6 +9,7 @@ pub enum Version {
     Semver(semver::Version),
     Lts(LtsType),
     Alias(String),
+    Latest,
     Bypassed,
 }
 
@@ -58,7 +59,7 @@ impl Version {
     pub fn installation_path(&self, config: &config::FnmConfig) -> std::path::PathBuf {
         match self {
             Self::Bypassed => system_version::path(),
-            v @ (Self::Lts(_) | Self::Alias(_)) => {
+            v @ (Self::Lts(_) | Self::Alias(_) | Self::Latest) => {
                 config.aliases_dir().join(v.alias_name().unwrap())
             }
             v @ Self::Semver(_) => config
@@ -93,6 +94,7 @@ impl std::fmt::Display for Version {
             Self::Lts(lts) => write!(f, "lts-{}", lts),
             Self::Semver(semver) => write!(f, "v{}", semver),
             Self::Alias(alias) => write!(f, "{}", alias),
+            Self::Latest => write!(f, "latest"),
         }
     }
 }
@@ -107,7 +109,7 @@ impl FromStr for Version {
 impl PartialEq<semver::Version> for Version {
     fn eq(&self, other: &semver::Version) -> bool {
         match self {
-            Self::Bypassed | Self::Lts(_) | Self::Alias(_) => false,
+            Self::Bypassed | Self::Lts(_) | Self::Alias(_) | Self::Latest => false,
             Self::Semver(v) => v == other,
         }
     }