stuff

buildfiles/app/node_modules/eslint/lib/rules/no-empty-character-class.js

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+/**
+ * @fileoverview Rule to flag the use of empty character classes in regular expressions
+ * @author Ian Christian Myers
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+/*
+ * plain-English description of the following regexp:
+ * 0. `^` fix the match at the beginning of the string
+ * 1. `\/`: the `/` that begins the regexp
+ * 2. `([^\\[]|\\.|\[([^\\\]]|\\.)+\])*`: regexp contents; 0 or more of the following
+ * 2.0. `[^\\[]`: any character that's not a `\` or a `[` (anything but escape sequences and character classes)
+ * 2.1. `\\.`: an escape sequence
+ * 2.2. `\[([^\\\]]|\\.)+\]`: a character class that isn't empty
+ * 3. `\/` the `/` that ends the regexp
+ * 4. `[gimuy]*`: optional regexp flags
+ * 5. `$`: fix the match at the end of the string
+ */
+const regex = /^\/([^\\[]|\\.|\[([^\\\]]|\\.)+\])*\/[gimuys]*$/u;
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = {
+    meta: {
+        type: "problem",
+
+        docs: {
+            description: "disallow empty character classes in regular expressions",
+            category: "Possible Errors",
+            recommended: true,
+            url: "https://eslint.org/docs/rules/no-empty-character-class"
+        },
+
+        schema: [],
+
+        messages: {
+            unexpected: "Empty class."
+        }
+    },
+
+    create(context) {
+        const sourceCode = context.getSourceCode();
+
+        return {
+
+            Literal(node) {
+                const token = sourceCode.getFirstToken(node);
+
+                if (token.type === "RegularExpression" && !regex.test(token.value)) {
+                    context.report({ node, messageId: "unexpected" });
+                }
+            }
+
+        };
+
+    }
+};