catch any valid identifier field

src/backends/backend.js

@@ -41,23 +41,28 @@ class LocalStorageAuthStore {
   }
 }
 
-const slugFormatter = (template = "{{slug}}", entryData, slugConfig) => {
-  const date = new Date();
-
-  const getIdentifier = (entryData) => {
-    const validIdentifierFields = ["title", "path"];
-    const identifiers = validIdentifierFields.map((field) =>
-      entryData.find((_, key) => key.toLowerCase().trim() === field)
-    );
+const validIdentifierFields = ["title", "path"];
 
-    const identifier = identifiers.find(ident => ident !== undefined);
+const getIdentifierKey = entryData => {
+  const keys = validIdentifierFields.map(field => {
+    return entryData.findKey((_, key) => {
+      return key.toLowerCase().trim() === field;
+    });
+  });
+  return keys.find(key => entryData.get(key) !== undefined);
+};
 
-    if (identifier === undefined) {
-      throw new Error("Collection must have a field name that is a valid entry identifier");
-    }
+const getIdentifier = entryData => {
+  const key = getIdentifierKey(entryData);
+  const identifier = entryData.get(key);
+  if (identifier === undefined) {
+    throw new Error("Collection must have a field name that is a valid entry identifier");
+  }
+  return identifier;
+};
 
-    return identifier;
-  };
+const slugFormatter = (template = "{{slug}}", entryData, slugConfig) => {
+  const date = new Date();
 
   const slug = template.replace(/\{\{([^\}]+)\}\}/g, (_, field) => {
     switch (field) {
@@ -234,23 +239,34 @@ class Backend {
     .then(this.entryWithFormat(collection, slug));
   }
 
-  async checkOverwrite(collection, slug, path, entryDraft) {
-    const errorMessage = "Oops, duplicate filename found. Please choose a unique name.";
-    const existingEntry = await this.unpublishedEntry(collection, slug).catch(error => (
-      (error instanceof EditorialWorkflowError && error.notUnderEditorialWorkflow) ?
-      Promise.resolve(false) : 
-      Promise.reject(error)));
+  async checkOverwrite(collection, slug, path, entryData) {
+    const identifierKey = getIdentifierKey(entryData);
+    const identifierField = collection.get('fields').find(field => {
+      return field.get('name') === identifierKey;
+    });
+    const identifierLabel = identifierField.get('label');
+    const errorMessage = `\
+Duplicate filename found. Please ensure the ${identifierLabel} field is unique from other entries \
+in the ${collection.get('name')} collection.\
+`;
+
+    const existingEntry = await this.unpublishedEntry(collection, slug).catch(error => {
+      if (error instanceof EditorialWorkflowError && error.notUnderEditorialWorkflow) {
+        return Promise.resolve(false);
+      }
+      return Promise.reject(error);
+    });
 
-    if (existingEntry) throw (new Error(errorMessage));
+    if (existingEntry) {
+      throw new Error(errorMessage);
+    }
 
     const publishedEntry = await this.implementation.getEntry(collection, slug, path)
-      .then(result => {
-        return result.data;
-      });
-
-    if (publishedEntry) throw (new Error(errorMessage));
+      .then(({ data }) => data);
 
-    return {path, slug, raw: this.entryToRaw(collection, entryDraft.get("entry"))};
+    if (publishedEntry) {
+      throw new Error(errorMessage);
+    }
   }
 
   async persistEntry(config, collection, entryDraft, MediaFiles, integrations, options = {}) {
@@ -267,9 +283,17 @@ class Backend {
       if (!selectAllowNewEntries(collection)) {
         throw (new Error("Not allowed to create new entries in this collection"));
       }
-      const slug = slugFormatter(collection.get("slug"), entryDraft.getIn(["entry", "data"]), config.get("slug"));
+      const entryData = entryDraft.getIn(['entry', 'data']);
+      const slug = slugFormatter(collection.get('slug'), entryData, config.get('slug'));
       const path = selectEntryPath(collection, slug);
-      entryObj = await this.checkOverwrite(collection, slug, path, entryDraft);
+
+      await this.checkOverwrite(collection, slug, path, entryData);
+
+      entryObj = {
+        path,
+        slug,
+        raw: this.entryToRaw(collection, entryDraft.get('entry')),
+      };
     } else {
       const path = entryDraft.getIn(["entry", "path"]);
       const slug = entryDraft.getIn(["entry", "slug"]);