Refactored computations again, split into multiple files, lots still to do

app/imports/api/creature/computation/evaluateCalculation.js

@@ -0,0 +1,30 @@
+import computedValueOfVariableName from '/imports/api/creature/computation/computedValueOfVariableName.js'
+
+export default function evaluateCalculation(string, memo){
+  if (!string) return string;
+  // Parse the string using mathjs
+  let calc;
+  try {
+    calc = math.parse(string);
+  } catch (e) {
+    return string;
+  }
+  // Replace all symbols with known values
+  let substitutedCalc = calc.transform(node => {
+    if (node.isSymbolNode) {
+      let val = computedValueOfVariableName(node.name, memo);
+      if (val === null) return node;
+      return new math.expression.node.ConstantNode(val);
+    }
+    else {
+      return node;
+    }
+  });
+
+  // Evaluate the expression to a number or return with substitutions
+  try {
+    return substitutedCalc.eval();
+  } catch (e){
+    return substitutedCalc.toString();
+  }
+}