From e5b173155a78729e58fc33e14f302c554f9035c0 Mon Sep 17 00:00:00 2001
From: Emma <emma@cyborggrizzly.com>
Date: Tue, 20 May 2025 10:22:49 -0600
Subject: [PATCH] feat: change evaluation now adds case transformation for
 capture groups

---
 tools/fieldRename.ts   | 40 ++++++++++++++++++++++++++++-----
 util/caseManagement.ts | 50 +++++++++++++++++++++++++++++++++++++-----
 2 files changed, 80 insertions(+), 10 deletions(-)

diff --git a/tools/fieldRename.ts b/tools/fieldRename.ts
index e99b4e9..9fb6868 100644
--- a/tools/fieldRename.ts
+++ b/tools/fieldRename.ts
@@ -7,6 +7,7 @@ import { colorize } from "../cli/style.ts";
 import { cliAlert, cliLog, cliPrompt } from "../cli/prompts.ts";
 import { multiSelectMenuInteractive } from "../cli/selectMenu.ts";
 import type { callback, ITool } from "../types.ts";
+import { toCase } from "util/caseManagement.ts";
 
 async function renameFields(
   path: string,
@@ -69,13 +70,42 @@ function applyRename(
   }
 }
 
+/***
+ * Evaluates the change string with the match array
+ *
+ * @description The change string can include the following variables:
+ *
+ * - $<int> - capture groups, indexed from 1
+ * - $<int>i - capture groups, indexed from 1, transforming an integer to an index
+ * - $<int>s - capture groups, indexed from 1, transforming a string to snake case
+ * - $<int>c - capture groups, indexed from 1, transforming a string to camel case
+ * - $<int>l - capture groups, indexed from 1, transforming a string to lower case
+ * - $<int>u - capture groups, indexed from 1, transforming a string to upper case
+ * - $<int>t - capture groups, indexed from 1, transforming a string to title case
+ */
 function evaluateChange(change: string, match: RegExpExecArray) {
   return change.replace(
-    /\$(\d+)(i?)/g,
-    (_, i, indexed) =>
-      indexed
-        ? (parseInt(match[i]) ? (parseInt(match[i]) - 1).toString() : match[i])
-        : match[i],
+    /\$(\d+)([icslut]?)/g,
+    (_, i, indexed) => {
+      switch (indexed) {
+        case "i":
+          return (parseInt(match[i])
+            ? (parseInt(match[i]) - 1).toString()
+            : match[i]);
+        case "s":
+          return toCase(match[i], "snake");
+        case "c":
+          return toCase(match[i], "camel");
+        case "t":
+          return toCase(match[i], "title");
+        case "l":
+          return match[i].toLowerCase();
+        case "u":
+          return match[i].toUpperCase();
+        default:
+          return match[i];
+      }
+    },
   );
 }
 
diff --git a/util/caseManagement.ts b/util/caseManagement.ts
index d538c68..b5a4566 100644
--- a/util/caseManagement.ts
+++ b/util/caseManagement.ts
@@ -11,9 +11,45 @@ function lowerToTrainCase(str: string) {
   );
 }
 
-function lowerToCamelCase(str: string) {
-  return str.trim().replace(/(?:\s)\w/g, (match) => match.toUpperCase())
-    .replaceAll(" ", "");
+/**
+ * @param str
+ * @returns camelCased string (single letter words are lower cased, e.g. SSN -> ssn)
+ */
+function lowerToCamelCase(str: string): string {
+  const words = str.trim().split(/\s+/);
+  const result: string[] = [];
+  let i = 0;
+
+  while (i < words.length) {
+    if (words[i].length === 1) {
+      // We’ve hit the start of a chain of single-letter words
+      let j = i;
+      while (j < words.length && words[j].length === 1) {
+        j++;
+      }
+      const chainIsAtStart = i === 0;
+      // Process that entire chain
+      for (let k = i; k < j; k++) {
+        result[k] = chainIsAtStart
+          ? words[k].toLowerCase()
+          : words[k].toUpperCase();
+      }
+      i = j;
+    } else {
+      // Normal multi-letter word
+      if (i === 0) {
+        // first word: all lower
+        result[i] = words[i].toLowerCase();
+      } else {
+        // subsequent words: capitalize first letter
+        result[i] = words[i][0].toUpperCase() +
+          words[i].slice(1).toLowerCase();
+      }
+      i++;
+    }
+  }
+
+  return result.join("");
 }
 
 function lowerToSnakeCase(str: string) {
@@ -88,10 +124,10 @@ function coerceCaseToLower(str: string, caseType: CaseType) {
     case "macro":
     case "snake":
     case "upper":
-      return str.replace("_", " ").toLowerCase();
+      return str.replaceAll("_", " ").toLowerCase();
     case "train":
     case "kebab":
-      return str.replace("-", " ").toLowerCase();
+      return str.replaceAll("-", " ").toLowerCase();
     default:
       return str.toLowerCase();
   }
@@ -124,3 +160,7 @@ export function toCase(str: string, toCase: CaseType) {
       return str;
   }
 }
+
+if (import.meta.main) {
+  console.log(toCase("SSN", "camel"));
+}