fix(24parser): catch mathjs compilation failure (#125)

* mathjs import fix

* add try-catch for parser compilation

* change target in response message

* revert bracing to prior style

Author: imagine-hussain

commands/24parser.js

@@ -1,14 +1,36 @@
 const { SlashCommandBuilder } = require("@discordjs/builders");
-const { isNaN } = require("mathjs");
-const { Util } = require("discord.js");
 const math = require("mathjs");
+const { Util } = require("discord.js");
 
 const illegalPhraseRegexes = [/`/g, /@/g];
 
 const isIllegalCharactersPresent = (expression) => {
     return illegalPhraseRegexes.some((regex) => regex.test(expression));
 };
 
+const tryCompileAndEvaluate = (eqnString) => {
+    try {
+        const equationObj = math.compile(eqnString);
+        if (!equationObj) {
+            throw Error;
+        }
+
+        const equationOutcome = equationObj.evaluate();
+
+        return {
+            success: true,
+            equationOutcome,
+        };
+
+    } catch (e) {
+        return {
+            success: false,
+            message: "Could not compile. The equation is invalid.",
+            ephemeral: true,
+        };
+    }
+};
+
 const evaluate = (equationString, target) => {
     if (isIllegalCharactersPresent(equationString)) {
         return {
@@ -18,18 +40,18 @@ const evaluate = (equationString, target) => {
         };
     }
 
-    const equationObj = math.compile(equationString);
-    if (!equationObj) {
+    const evaluationOutcome = tryCompileAndEvaluate(equationString);
+    if (!evaluationOutcome.success) {
         return {
             success: false,
-            message: "Could not compile. The equation is invalid.",
+            message: evaluationOutcome.message,
             ephemeral: true,
         };
     }
+    const { equationOutcome } = evaluationOutcome;
 
-    const equationOutcome = equationObj.evaluate();
     const outcomeAsNumber = Number(equationOutcome);
-    if (isNaN(outcomeAsNumber)) {
+    if (math.isNaN(outcomeAsNumber)) {
         return {
             success: false,
             message: "Could not compile. The equation does not evaluate to a number.",
@@ -38,16 +60,17 @@ const evaluate = (equationString, target) => {
     }
 
     return outcomeAsNumber == target
-        ? {
-              success: true,
-              message: `Correct! \`${equationString}\` = ${target}, which is equal to the target of ${target}.`,
-              ephemeral: false,
-          }
-        : {
-              success: false,
-              message: `Incorrect. \`${equationString}\` = ${outcomeAsNumber}, which is not equal to the target of ${target}.`,
-              ephemeral: false,
-          };
+    ? {
+        success: true,
+        message: `Correct! \`${equationString}\` = ${target}, which is equal to the target.`,
+        ephemeral: false,
+      }
+    : {
+        success: false,
+        message: `Incorrect. \`${equationString}\` = ${outcomeAsNumber}, which is not equal to the target of ${target}.`,
+        ephemeral: false,
+    };
+
 };
 
 module.exports = {
@@ -75,3 +98,4 @@ module.exports = {
         });
     },
 };
+