[TASK] Implement @typescript-eslint/prefer-string-starts-ends-with …

…rule

The eslint configuration now takes the rule
`@typescript-eslint/prefer-string-starts-ends-with` [1] into account,
enforcing the usage of `startsWith()` and `endWith()` over index
checking in strings.

[1] https://typescript-eslint.io/rules/prefer-string-starts-ends-with

Resolves: #103374
Releases: main, 12.4
Change-Id: I88640f71cbe960db2a2e2b162410ff5a79e7c55c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/83448
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Benjamin Franzke <ben@bnf.dev>
Tested-by: Andreas Kienast <a.fernandez@scripting-base.de>
Reviewed-by: Andreas Kienast <a.fernandez@scripting-base.de>

Build/.eslintrc.js

@@ -37,6 +37,7 @@ module.exports = {
     "@typescript-eslint/no-unused-vars": "error",
     "@typescript-eslint/member-ordering": "error",
     "@typescript-eslint/prefer-readonly": "error",
+    "@typescript-eslint/prefer-string-starts-ends-with": "error",
     "@typescript-eslint/naming-convention": [
       "error",
       {

Build/Sources/TypeScript/backend/form-engine-validation.ts

@@ -646,7 +646,7 @@ export default (function() {
   FormEngineValidation.parseDouble = function(value: number|string|boolean, precision: number = 2): string {
     let theVal = '' + value;
     theVal = theVal.replace(/[^0-9,.-]/g, '');
-    const negative = theVal.substring(0, 1) === '-';
+    const negative = theVal.startsWith('-');
     theVal = theVal.replace(/-/g, '');
     theVal = theVal.replace(/,/g, '.');
     if (theVal.indexOf('.') === -1) {

Build/Sources/TypeScript/core/ajax/ajax-request.ts

@@ -161,7 +161,7 @@ class AjaxRequest {
 
   private composeRequestUrl(): string {
     let url = this.url;
-    if (url.charAt(0) === '?') {
+    if (url.startsWith('?')) {
       // URL is a search string only, prepend current location
       url = window.location.origin + window.location.pathname + url;
     }

Build/Sources/TypeScript/core/requirejs-loader.ts

@@ -203,7 +203,7 @@ interface Require {
 
     if (
       inPath(context.config, name) ||
-      url.charAt(0) === '/' ||
+      url.startsWith('/') ||
       (context.config.typo3BaseUrl as unknown as boolean) === false
     ) {
       originalLoad.call(req, context, name, url);

Build/Sources/TypeScript/rte_ckeditor/rte-link-browser.ts

@@ -92,7 +92,7 @@ class RteLinkBrowser {
       link = linkMatch[1] + linkMatch[2];
       const paramsPrefix = linkMatch[2].length > 0 ? '&' : '?';
       if (queryParams.length > 0) {
-        if (queryParams[0] === '&') {
+        if (queryParams.startsWith('&')) {
           queryParams = queryParams.substr(1);
         }
         // If params is set, append it

Build/Sources/TypeScript/t3editor/autocomplete/ts-code-completion.ts

@@ -97,7 +97,7 @@ export class TsCodeCompletion {
       let childNode;
       // if the childnode has a value and there is a part of a reference operator ('<')
       // and it does not look like a html tag ('>')
-      if (childNodes[key].v && childNodes[key].v[0] === '<' && childNodes[key].v.indexOf('>') === -1) {
+      if (childNodes[key].v && childNodes[key].v.startsWith('<') && !childNodes[key].v.includes('>')) {
         const path = childNodes[key].v.replace(/</, '').trim();
         // if there are still whitespaces it's no path
         if (path.indexOf(' ') === -1) {

Build/Sources/TypeScript/t3editor/autocomplete/ts-parser.ts

@@ -191,11 +191,11 @@ export class TsParser {
         if (i < tokens.length && tokens[i].string.length > 0) {
           const tokenValue = tokens[i].string;
 
-          if (tokenValue[0] === '#') {
+          if (tokenValue.startsWith('#')) {
             stack.push('#');
           } else if (tokenValue === '(') {
             stack.push('(');
-          } else if (tokenValue[0] === '/' && tokenValue[1] === '*') {
+          } else if (tokenValue.startsWith('/*')) {
             stack.push('/*');
           } else if (tokenValue === '{') {
             // TODO: ignore whole block if wrong whitespaces in this line
@@ -237,7 +237,7 @@ export class TsParser {
           if (tokenValue === ')') {
             stack.popIfLastElementEquals('(');
           }
-          if (tokenValue[0] === '*' && tokenValue[1] === '/') {
+          if (tokenValue.startsWith('*/')) {
             stack.popIfLastElementEquals('/*');
             ignoreLine = true;
           }