feat(sdk): dynamic-context-validation

Author: tractorss

kleros-sdk/src/dataMappings/utils/replacePlaceholdersWithValues.ts

@@ -1,8 +1,10 @@
 import mustache from "mustache";
+import retrieveVariables from "./retrieveVariables";
 
 export const replacePlaceholdersWithValues = (mapping: any, context: Record<string, unknown>) => {
   const replace = (obj) => {
     if (typeof obj === "string") {
+      validateContext(obj, context);
       return mustache.render(obj, context);
     } else if (Array.isArray(obj)) {
       return obj.map(replace);
@@ -15,3 +17,18 @@ export const replacePlaceholdersWithValues = (mapping: any, context: Record<stri
 
   return replace(mapping);
 };
+
+/**
+ *
+ * @param template
+ * @param context
+ * @description retrieves all variables from a template and validates if they are provided in the context
+ */
+const validateContext = (template: string, context: Record<string, unknown>) => {
+  const variables = retrieveVariables(template);
+
+  variables.forEach((variable) => {
+    if (!context[variable]) throw new Error(`Expected key :  "${variable}" to be provided in context.`);
+  });
+  return true;
+};

kleros-sdk/src/dataMappings/utils/retrieveVariables.ts

@@ -0,0 +1,20 @@
+import mustache from "mustache";
+
+/**
+ *
+ * @param template
+ * @returns Variables[] returns the variables in a template string
+ * @note This is a naive implementation and wil not work for complex tags, only works for {{}} and {{{}}} tags for now.
+ *       Reference : https://github.com/janl/mustache.js/issues/538
+ */
+const retrieveVariables = (template: string) =>
+  mustache
+    .parse(template)
+    .filter(function (v) {
+      return v[0] === "name" || v[0] === "&";
+    }) // add more conditions here to include more tags
+    .map(function (v) {
+      return v[1];
+    });
+
+export default retrieveVariables;