Instead of using eval to get things out of the Math object, we can use aset. Solution from David at Hack and Tell. Thanks!
1 files changed, 2 insertions(+), 2 deletions(-)

M src/cljs/calculator/calculator.cljs
M src/cljs/calculator/calculator.cljs +2 -2
@@ 143,8 143,8 @@ 
           (operator->function lower-operator)
           (when (or (.hasOwnProperty js/Math upper-operator)
                     (.hasOwnProperty js/Math lower-operator))
-            (let [function-or-constant (or (js/eval (str "Math." upper-operator))
-                                           (js/eval (str "Math." lower-operator)))]
+            (let [function-or-constant (or (aget js/Math upper-operator)
+                                           (aget js/Math lower-operator))]
               (cond (number? function-or-constant)
                     (constant-operation function-or-constant)
                     (fn? function-or-constant)