fix: report an error for an unknown target in the JS binding

CHANGELOG.md

@@ -54,6 +54,13 @@
 
 **Integrations**:
 
+- The `prqlc` JS/wasm package now reports an error for an unknown `target`,
+  rather than silently compiling to generic SQL. A typo such as
+  `opts.target = "sql.postgrez"` previously fell back to `sql.any`, so the
+  caller got working-but-wrong SQL with no signal. The Python and C bindings
+  already propagated this error; an unset (empty) `target` still means
+  `sql.any`. (@prql-bot, #6238)
+
 - The `prqlc` Python package now declares `requires-python = ">=3.10"`. Python
   3.9 reached end-of-life in October 2025 and was never exercised by the test
   matrix, which runs 3.10 and 3.12. The stale `>=3.9` claim also blocked every

prqlc/bindings/js/src/lib.rs

@@ -7,9 +7,13 @@ use wasm_bindgen::prelude::*;
 
 #[wasm_bindgen]
 pub fn compile(prql_query: &str, options: Option<CompileOptions>) -> Option<String> {
+    let options = match options.map(prqlc::Options::try_from).transpose() {
+        Ok(options) => options.unwrap_or_default(),
+        Err(e) => return return_or_throw(Err(e)),
+    };
+
     return_or_throw(
-        prqlc::compile(prql_query, &options.map(|x| x.into()).unwrap_or_default())
-            .map_err(|e| e.composed(&prql_query.into())),
+        prqlc::compile(prql_query, &options).map_err(|e| e.composed(&prql_query.into())),
     )
 }
 
@@ -109,17 +113,26 @@ impl CompileOptions {
     }
 }
 
-impl From<CompileOptions> for prqlc::Options {
-    fn from(o: CompileOptions) -> Self {
-        let target = Target::from_str(&o.target).unwrap_or_default();
+impl TryFrom<CompileOptions> for prqlc::Options {
+    type Error = prqlc::ErrorMessages;
+
+    fn try_from(o: CompileOptions) -> Result<Self, Self::Error> {
+        // An empty `target` is the unset default, and means `sql.any`. Anything
+        // else has to parse — otherwise a typo such as `sql.postgrez` would
+        // silently compile to generic SQL.
+        let target = if o.target.is_empty() {
+            Target::default()
+        } else {
+            Target::from_str(&o.target).map_err(prqlc::ErrorMessages::from)?
+        };
 
-        prqlc::Options {
+        Ok(prqlc::Options {
             format: o.format,
             target,
             signature_comment: o.signature_comment,
             display: prqlc::DisplayOptions::Plain,
             ..Default::default()
-        }
+        })
     }
 }
 

prqlc/bindings/js/tests/test_all.mjs

@@ -70,6 +70,30 @@ describe("prqlc-js", () => {
       );
       assert(res.includes("target:sql.mssql"));
     });
+
+    it("should throw on an unknown target rather than silently using sql.any", () => {
+      const opts = new prqlc.CompileOptions();
+      opts.target = "sql.postgrez";
+
+      expect(() => prqlc.compile("from a | take 10", opts)).to.throw(
+        "sql.postgrez",
+      );
+    });
+
+    it("should treat an unset target as sql.any", () => {
+      const opts = new prqlc.CompileOptions();
+      opts.format = false;
+      opts.signature_comment = false;
+
+      const res = prqlc.compile(
+        "prql target:sql.mssql\nfrom a | take 10",
+        opts,
+      );
+      assert.equal(
+        res,
+        "SELECT * FROM a ORDER BY (SELECT NULL) OFFSET 0 ROWS FETCH FIRST 10 ROWS ONLY",
+      );
+    });
   });
 
   describe("prql_to_pl", () => {