feat: add limit-length option

src/jnv.rs

@@ -35,11 +35,18 @@ mod keymap;
 /// # Returns
 /// An `anyhow::Result` wrapping a vector of `serde_json::Value`. On success, it contains the parsed
 /// JSON data. On failure, it contains an error detailing what went wrong during parsing.
-fn deserialize_json(json_str: &str) -> anyhow::Result<Vec<serde_json::Value>> {
-    Deserializer::from_str(json_str)
-        .into_iter::<serde_json::Value>()
-        .map(|res| res.map_err(anyhow::Error::from))
-        .collect::<anyhow::Result<Vec<serde_json::Value>>>()
+fn deserialize_json(json_str: &str, limit_length: Option<usize>) -> anyhow::Result<Vec<serde_json::Value>> {
+    match limit_length {
+        Some(l) => Deserializer::from_str(json_str)
+            .into_iter::<serde_json::Value>()
+            .take(l)
+            .map(|res| res.map_err(anyhow::Error::from))
+            .collect::<anyhow::Result<Vec<serde_json::Value>>>(),
+        None => Deserializer::from_str(json_str)
+            .into_iter::<serde_json::Value>()
+            .map(|res| res.map_err(anyhow::Error::from))
+            .collect::<anyhow::Result<Vec<serde_json::Value>>>(),
+    }
 }
 
 fn run_jq(query: &str, json_stream: &[serde_json::Value]) -> anyhow::Result<Vec<String>> {
@@ -96,6 +103,7 @@ pub struct Jnv {
     suggest: Suggest,
 
     json_expand_depth: Option<usize>,
+    json_limit_length: Option<usize>,
     no_hint: bool,
 }
 
@@ -107,9 +115,10 @@ impl Jnv {
         suggestions: listbox::State,
         json_theme: json::Theme,
         json_expand_depth: Option<usize>,
+        json_limit_length: Option<usize>,
         no_hint: bool,
     ) -> Result<Prompt<Self>> {
-        let input_stream = deserialize_json(&input)?;
+        let input_stream = deserialize_json(&input, json_limit_length)?;
 
         let mut trie = FilterTrie::default();
         trie.insert(".", input_stream.clone());
@@ -160,6 +169,7 @@ impl Jnv {
                 trie,
                 suggest,
                 json_expand_depth,
+                json_limit_length,
                 no_hint,
                 input_stream,
             },
@@ -252,7 +262,7 @@ impl promkit::Renderer for Jnv {
                                         JsonStream::new(searched.clone(), self.json_expand_depth);
                                 }
                             } else {
-                                match deserialize_json(&ret.join("\n")) {
+                                match deserialize_json(&ret.join("\n"), self.json_limit_length) {
                                     Ok(jsonl) => {
                                         let stream =
                                             JsonStream::new(jsonl.clone(), self.json_expand_depth);

src/main.rs

@@ -99,6 +99,18 @@ pub struct Args {
     )]
     pub json_expand_depth: Option<usize>,
 
+    #[arg(
+        short = 's',
+        long = "limit-length",
+        default_value = "50",
+        help = "Limit length of JSON array in the visualization.",
+        long_help = "
+        Specifies the limit length to load JSON array in the visualization.
+        Note: Increasing this length can significantly slow down the display for large datasets.
+        "
+    )]
+    pub json_limit_length: Option<usize>,
+
     #[arg(
         short = 'l',
         long = "suggestion-list-length",
@@ -208,6 +220,7 @@ fn main() -> Result<()> {
         suggestions,
         json_theme,
         args.json_expand_depth,
+        args.json_limit_length,
         args.no_hint,
     )?;
     let _ = prompt.run()?;