Tag known-numeric infix and bit ops to skip nullish coalesce in str

Author: willcohen

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 [Squint](https://github.com/squint-cljs/squint): Light-weight ClojureScript dialect
 
+## Unreleased
+
+- Fix [#815](https://github.com/squint-cljs/squint/issues/815): `str` wrapping known-numeric infix expressions in `??''`, which esbuild flagged as `suspicious-nullish-coalescing`.
+
 ## 0.11.189
 
 - [#809](https://github.com/squint-cljs/squint/issues/809): add `squint.compiler/compile*` and `squint.compiler/transpile*` which accept either a string or a sequence of pre-parsed forms, skipping the `forms -> string -> forms` roundtrip for SSR use cases. The previous names `compile-string*` / `transpile-string*` are retained as deprecated aliases.

src/squint/compiler_common.cljc

@@ -242,6 +242,10 @@
 (def boolean-infix-operators
   #{"==" "===" "<" ">" "<=" ">=" "!=" "instanceof"})
 
+(def numeric-infix-operators
+  #{"+" "+=" "-" "-=" "/" "*" "%" "<<" ">>" "<<<" ">>>" "&" "|"
+    "bit-or" "bit-and" "js-mod"})
+
 (def chainable-infix-operators #{"+" "-" "*" "/" "&" "|" "&&" "||" "bit-or" "bit-and" "js-??"})
 
 (defn infix-operator? [env expr]
@@ -263,7 +267,8 @@
   (let [env (assoc enc-env :context :expr :top-level false)
         acount (count args)
         op-name (name operator)
-        bool? (contains? boolean-infix-operators op-name)]
+        bool? (contains? boolean-infix-operators op-name)
+        numeric? (contains? numeric-infix-operators op-name)]
     (if (and (not (chainable-infix-operators op-name)) (> acount 2))
       (emit (list 'cljs.core/&&
                   (list operator (first args) (second args))
@@ -289,7 +294,8 @@
        wrap-parens
        (emit-return enc-env)
        (cond->
-           bool? (tagged-expr 'boolean))))))
+           bool? (tagged-expr 'boolean)
+           numeric? (tagged-expr 'number))))))
 
 (def core-vars (atom #{}))
 
@@ -980,10 +986,12 @@
   (emit-return (wrap-parens (str "new " (emit class (expr-env env)) (comma-list (emit-args env args)))) env))
 
 (defmethod emit-special 'dec [_type env [_ var]]
-  (emit-return (str "(" (emit var (assoc env :context :expr)) " - " 1 ")") env))
+  (-> (emit-return (str "(" (emit var (assoc env :context :expr)) " - " 1 ")") env)
+      (tagged-expr 'number)))
 
 (defmethod emit-special 'inc [_type env [_ var]]
-  (emit-return (str "(" (emit var (assoc env :context :expr)) " + " 1 ")") env))
+  (-> (emit-return (str "(" (emit var (assoc env :context :expr)) " + " 1 ")") env)
+      (tagged-expr 'number)))
 
 (defmethod emit-special 'while [_type env [_while test & body]]
   (str "while (" (emit test (expr-env env)) ") { \n"

src/squint/internal/macros.cljc

@@ -306,6 +306,9 @@
 (defn- bool-expr [e]
   (vary-meta e assoc :tag 'boolean))
 
+(defn- num-expr [e]
+  (vary-meta e assoc :tag 'number))
+
 (defn core-exists?
   "Return true if argument exists, analogous to usage of typeof operator
    in JavaScript."
@@ -543,7 +546,7 @@
   (core/list 'js* "(~ ~{})" x))
 
 (core/defmacro ^::ana/numeric bit-and
-  ([x y] (core/list 'js* "(~{} & ~{})" x y))
+  ([x y] (num-expr (core/list 'js* "(~{} & ~{})" x y)))
   ([x y & more] `(cc/bit-and (cc/bit-and ~x ~y) ~@more)))
 
 ;; internal do not use
@@ -552,7 +555,7 @@
   ([x y & more] `(cc/unsafe-bit-and (cc/unsafe-bit-and ~x ~y) ~@more)))
 
 (core/defmacro ^::ana/numeric bit-or
-  ([x y] (core/list 'js* "(~{} | ~{})" x y))
+  ([x y] (num-expr (core/list 'js* "(~{} | ~{})" x y)))
   ([x y & more] `(cc/bit-or (cc/bit-or ~x ~y) ~@more)))
 
 (core/defmacro ^::ana/numeric int [x]