import rewritePattern from "regexpu-core";
import * as regex from "@babel/helper-regex";

export default function() {
  return {
    visitor: {
      RegExpLiteral(path, state) {
        const node = path.node;
        if (!regex.is(node, "u")) {
          return;
        }
        const useUnicodeFlag = state.opts.useUnicodeFlag || false;
        node.pattern = rewritePattern(node.pattern, node.flags, {
          unicodePropertyEscape: true,
          useUnicodeFlag: useUnicodeFlag,
        });
        if (!useUnicodeFlag) {
          regex.pullFlag(node, "u");
        }
      },
    },
  };
}