Babel Helper Regex

import * as regex from "babel-helper-regex";
import { is, pullFlag } from "babel-helper-regex";

const regex = require("babel-helper-regex");
const { is, pullFlag } = require("babel-helper-regex");

import * as regex from "babel-helper-regex";
import * as t from "babel-types";

// Example: Check if a RegExp literal has the unicode flag
export default function () {
  return {
    visitor: {
      RegExpLiteral({ node }) {
        // Check if node has unicode flag
        if (regex.is(node, "u")) {
          // Process the node with unicode flag
          console.log("Found unicode regex:", node.pattern);
          
          // Remove the unicode flag after processing
          regex.pullFlag(node, "u");
        }
      }
    }
  };
}

/**
 * Checks if a node is a RegExp literal with a specific flag
 * @param {Object} node - Babel AST node to check (must be RegExp literal)
 * @param {string} flag - The flag to look for ('g', 'i', 'm', 's', 'u', 'y')
 * @returns {boolean} true if the node is a RegExp literal and contains the specified flag
 */
function is(node, flag);

import * as regex from "babel-helper-regex";
import * as t from "babel-types";

// Create a RegExp literal node for testing
const regexNode = t.regExpLiteral("test", "gui");

// Check for different flags
console.log(regex.is(regexNode, "g")); // true
console.log(regex.is(regexNode, "u")); // true  
console.log(regex.is(regexNode, "y")); // false

// Works with any valid RegExp flags
console.log(regex.is(regexNode, "i")); // true (ignoreCase)
console.log(regex.is(regexNode, "m")); // false (multiline)
console.log(regex.is(regexNode, "s")); // false (dotAll)

/**
 * Removes a flag from a RegExp literal node
 * @param {Object} node - Babel AST node representing a RegExp literal
 * @param {string} flag - The flag to remove ('g', 'i', 'm', 's', 'u', 'y')
 * @returns {void} Mutates the node.flags property in place
 */
function pullFlag(node, flag);

import * as regex from "babel-helper-regex";
import * as t from "babel-types";

// Create a RegExp literal with multiple flags
const regexNode = t.regExpLiteral("pattern", "guiy");
console.log(regexNode.flags); // "guiy"

// Remove the unicode flag
regex.pullFlag(regexNode, "u");
console.log(regexNode.flags); // "giy"

// Remove global flag
regex.pullFlag(regexNode, "g");
console.log(regexNode.flags); // "iy"

// Removing non-existent flag does nothing
regex.pullFlag(regexNode, "m");
console.log(regexNode.flags); // "iy" (unchanged)

/**
 * Babel AST node representing a regular expression literal
 * This is provided by babel-types package
 */
interface RegExpLiteral {
  type: "RegExpLiteral";
  pattern: string;    // The regex pattern without delimiters
  flags: string;      // String containing flag characters (e.g., "gui")
}

/**
 * Valid RegExp flag characters
 */
type RegExpFlag = "g" | "i" | "m" | "s" | "u" | "y";