feat: change behaviour of mapFieldInteractive to allow fields to be passed as-is

Author: ksambhi

email/mailmerge-cli/src/interactivity/mapFieldsInteractive.ts

@@ -32,6 +32,8 @@ export const mapFieldsInteractive = async (
     logger.debug("Mapping CSV fields to template interactively");
 
     const NONE_OPTION = "None";
+    const PASS_AS_IS_OPTION = (field: string) =>
+        `Pass as-is (field '${field}' will be provided as field '${field}' to the templating engine)`;
 
     logger.info("When prompted, select the corresponding template field for each CSV header");
 
@@ -42,16 +44,30 @@ export const mapFieldsInteractive = async (
             type: "list",
             name: header,
             message: `Map CSV field \`${header}\` to template field:`,
-            choices: Array.from(templateFields).concat([NONE_OPTION]),
+            choices: Array.from(templateFields).concat([PASS_AS_IS_OPTION(header), NONE_OPTION]),
             // Set default to index in templateField that matches the csvHeader
-            default: templateFields.has(header) ? header : "None",
+            default: templateFields.has(header) ? header : PASS_AS_IS_OPTION(header),
         })),
     );
     for (const [csvHeader, templateFieldChosen] of Object.entries(await prompter).filter(
         ([, field]) => field !== NONE_OPTION,
     )) {
-        map.set(csvHeader, templateFieldChosen);
-        mappedFields.add(templateFieldChosen);
+        const fieldToSet =
+            templateFieldChosen === PASS_AS_IS_OPTION(csvHeader) ? csvHeader : templateFieldChosen;
+
+        if (map.has(csvHeader)) {
+            // Error, duplicate mapping, can't map the same csvHeader to two different templateFields (not yet anyway)
+            logger.error(
+                `Duplicate mapping for csvHeader \`${csvHeader}\` to template field \`${fieldToSet}\`! This is currently unsupported.`,
+            );
+
+            throw new Error(
+                `Duplicate mapping for csvHeader \`${csvHeader}\` to template field \`${fieldToSet}\`! This is currently unsupported.`,
+            );
+        }
+
+        map.set(csvHeader, fieldToSet);
+        mappedFields.add(fieldToSet);
     }
 
     // Warn if not all fields were mapped

email/workspace/data/names-list.json

@@ -0,0 +1,22 @@
+[
+    {
+        "name": "Kishan",
+        "to": "kishansambhi@hotmail.co.uk",
+        "subject": "DoCSoc x Kishan",
+        "alist": [
+            "One",
+            "Two",
+            "Three"
+        ]
+    },
+    {
+        "name": "NotKishan",
+        "to": "kishansambhi@hotmail.co.uk",
+        "subject": " DoCSoc x NotKishan",
+        "alist": [
+            "I",
+            "II",
+            "III"
+        ]
+    }
+]

email/workspace/templates/template-multi.md.njk

@@ -0,0 +1,18 @@
+Dear {{ name }},
+
+I hope you are well.
+
+If you are seeing this email, it means that the new mail merge tool is working as expected.
+
+For it was this email you see, that was sent by complete mail merge pipeline.
+
+Of course, some things are still missing, namely:
+{% for item in alist %}
+- {{ item }}{% endfor %}
+
+
+But it does work!
+
+Kind regards,
+Some TypeScript code on behalf of Kishan Sambhi (he/him)
+DoCSoc Vice President