ensureClientSideSelectorSupport = function ensureClientSideSelectorSupport() {
    var _this = this;

    return this.execute('return !!document.evaluate;').then(function (res) {
        if (res.value) {
            return true;
        }

        /**
         * Don't read in unless necessary
         */
        if (!wgxpathSrc) {
            wgxpathSrc = _fs2.default.readFileSync(WGXPATH_PATH);
            wgxpathSrc = wgxpathSrc.toString().split('module.exports')[0];
        }

        return _this.execute(wgxpathSrc + '\nwgxpath.install(window);');
    });
}
Ensures document.evaluate() in the browser.