vendors/execa.js/whichSync
    var whichSync = (cmd, opt) => {
      opt = opt || {};
      const { pathEnv, pathExt, pathExtExe } = getPathInfo(cmd, opt);
      const found = [];
      for (let i = 0; i < pathEnv.length; i++) {
        const ppRaw = pathEnv[i];
        const pathPart = /^".*"$/.test(ppRaw) ? ppRaw.slice(1, -1) : ppRaw;
        const pCmd = path3.join(pathPart, cmd);
        const p = !pathPart && /^\.[\\\/]/.test(cmd) ? cmd.slice(0, 2) + pCmd : pCmd;
        for (let j = 0; j < pathExt.length; j++) {
          const cur = p + pathExt[j];
          try {
            const is = isexe.sync(cur, { pathExt: pathExtExe });
            if (is) {
              if (opt.all)
                found.push(cur);
              else
                return cur;
            }
          } catch (ex) {
          }
        }
      }
      if (opt.all && found.length)
        return found;
      if (opt.nothrow)
        return null;
      throw getNotFoundError(cmd);
    };