From 0184de977a8b59d794dcdc89796cdbb784a4ab4a Mon Sep 17 00:00:00 2001
From: Josh Goldberg <git@joshuakgoldberg.com>
Date: Tue, 24 Jan 2023 18:05:20 -0500
Subject: [PATCH] Extract to shared helper

---
 .../eslint-plugin/src/rules/ban-ts-comment.ts | 18 ++----------------
 .../eslint-plugin/src/rules/key-spacing.ts    | 19 +++----------------
 .../eslint-plugin/src/util/getStringLength.ts | 17 +++++++++++++++++
 packages/eslint-plugin/src/util/index.ts      |  1 +
 4 files changed, 23 insertions(+), 32 deletions(-)
 create mode 100644 packages/eslint-plugin/src/util/getStringLength.ts

diff --git a/packages/eslint-plugin/src/rules/ban-ts-comment.ts b/packages/eslint-plugin/src/rules/ban-ts-comment.ts
index f0bfce93ff6..511a951280e 100644
--- a/packages/eslint-plugin/src/rules/ban-ts-comment.ts
+++ b/packages/eslint-plugin/src/rules/ban-ts-comment.ts
@@ -1,22 +1,7 @@
 import { AST_TOKEN_TYPES } from '@typescript-eslint/utils';
-import GraphemeSplitter from 'grapheme-splitter';
 
 import * as util from '../util';
 
-let splitter: GraphemeSplitter;
-function isASCII(value: string): boolean {
-  return /^[\u0020-\u007f]*$/u.test(value);
-}
-function getStringLength(value: string): number {
-  if (isASCII(value)) {
-    return value.length;
-  }
-
-  splitter ??= new GraphemeSplitter();
-
-  return splitter.countGraphemes(value);
-}
-
 type DirectiveConfig =
   | boolean
   | 'allow-with-description'
@@ -163,7 +148,8 @@ export default util.createRule<[Options], MessageIds>({
             } = options;
             const format = descriptionFormats.get(fullDirective);
             if (
-              getStringLength(description.trim()) < minimumDescriptionLength
+              util.getStringLength(description.trim()) <
+              minimumDescriptionLength
             ) {
               context.report({
                 data: { directive, minimumDescriptionLength },
diff --git a/packages/eslint-plugin/src/rules/key-spacing.ts b/packages/eslint-plugin/src/rules/key-spacing.ts
index dfd726708c3..587d2674f4f 100644
--- a/packages/eslint-plugin/src/rules/key-spacing.ts
+++ b/packages/eslint-plugin/src/rules/key-spacing.ts
@@ -1,24 +1,9 @@
 import type { TSESTree } from '@typescript-eslint/utils';
 import { AST_NODE_TYPES } from '@typescript-eslint/utils';
-import GraphemeSplitter from 'grapheme-splitter';
 
 import * as util from '../util';
 import { getESLintCoreRule } from '../util/getESLintCoreRule';
 
-let splitter: GraphemeSplitter;
-function isASCII(value: string): boolean {
-  return /^[\u0020-\u007f]*$/u.test(value);
-}
-function getStringLength(value: string): number {
-  if (isASCII(value)) {
-    return value.length;
-  }
-
-  splitter ??= new GraphemeSplitter();
-
-  return splitter.countGraphemes(value);
-}
-
 const baseRule = getESLintCoreRule('key-spacing');
 
 export type Options = util.InferOptionsTypeFromRule<typeof baseRule>;
@@ -55,7 +40,9 @@ export default util.createRule<Options, MessageIds>({
      */
     function adjustedColumn(position: TSESTree.Position): number {
       const line = position.line - 1; // position.line is 1-indexed
-      return getStringLength(sourceCode.lines[line].slice(0, position.column));
+      return util.getStringLength(
+        sourceCode.lines[line].slice(0, position.column),
+      );
     }
 
     /**
diff --git a/packages/eslint-plugin/src/util/getStringLength.ts b/packages/eslint-plugin/src/util/getStringLength.ts
new file mode 100644
index 00000000000..65a22551949
--- /dev/null
+++ b/packages/eslint-plugin/src/util/getStringLength.ts
@@ -0,0 +1,17 @@
+import GraphemeSplitter from 'grapheme-splitter';
+
+let splitter: GraphemeSplitter;
+
+function isASCII(value: string): boolean {
+  return /^[\u0020-\u007f]*$/u.test(value);
+}
+
+export function getStringLength(value: string): number {
+  if (isASCII(value)) {
+    return value.length;
+  }
+
+  splitter ??= new GraphemeSplitter();
+
+  return splitter.countGraphemes(value);
+}
diff --git a/packages/eslint-plugin/src/util/index.ts b/packages/eslint-plugin/src/util/index.ts
index b2ad2927773..53a19a96d36 100644
--- a/packages/eslint-plugin/src/util/index.ts
+++ b/packages/eslint-plugin/src/util/index.ts
@@ -5,6 +5,7 @@ export * from './collectUnusedVariables';
 export * from './createRule';
 export * from './getFunctionHeadLoc';
 export * from './getOperatorPrecedence';
+export * from './getStringLength';
 export * from './getThisExpression';
 export * from './getWrappingFixer';
 export * from './isNodeEqual';