How to use the @hpcc-js/util.exists function in @hpcc-js/util

}).then(response => {
            return exists("TargetClusterUsages.TargetClusterUsage", response) ? response.TargetClusterUsages.TargetClusterUsage : [];
        });
    }

connection.send(action, {}).then(response => {
                if (exists("Results.HIPIE_DDL.Row", response[responseID]) && response[responseID].Results.HIPIE_DDL.Row.length) {
                    this.importDDL(response[responseID].Results.HIPIE_DDL.Row[0].HIPIE_DDL, baseUrl, _url.param("Wuid"), layoutJson);
                }
            });
        } else if (_url.param("dsp")) {

connection.send(action, {}).then(function (response) {
                    if (util_1.exists("Results.HIPIE_DDL.Row", response[responseID_1]) && response[responseID_1].Results.HIPIE_DDL.Row.length) {
                        var ddl = JSON.parse(response[responseID_1].Results.HIPIE_DDL.Row[0].HIPIE_DDL);
                        _this._dashy.importDDL(ddl, baseUrl_2, _url.param("Wuid"));
                    }
                });
            }

return this.connection.TpServiceQuery({}).then(response => {
            const rootProtocol = this.connection.protocol();
            const ip = this.connection.ip();
            let port = rootProtocol === "https:" ? "18002" : "8002";
            if (exists("ServiceList.TpEspServers.TpEspServer", response)) {
                for (const item of response.ServiceList.TpEspServers.TpEspServer) {
                    if (exists("TpBindings.TpBinding", item)) {
                        for (const binding of item.TpBindings.TpBinding) {
                            if (binding.Service === type && binding.Protocol + ":" === rootProtocol) {
                                port = binding.Port;
                            }
                        }
                    }
                }
            }
            return `${rootProtocol}//${ip}:${port}/`;
        });
    }

bpGetValidLocations(filePath: any) {
        const retVal: any[] = [];
        if (exists("W_LOCAL.Graphs", this.jsonWU)) {
            let id = "";
            walkXmlJson(this.jsonWU.W_LOCAL.Graphs, (key: string, item: any, _stack: any[]) => {
                if (key === "$" && item.id) {
                    id = item.id;
                }
                if (key === "$" && item.name === "definition") {
                    const match = /([a-z,A-Z]:\\(?:[-\w\.\d]+\\)*(?:[-\w\.\d]+)?|(?:\/[\w\.\-]+)+)\((\d*),(\d*)\)/.exec(item.value);
                    if (match) {
                        const [, file, row, _col] = match;
                        const line: number = +row;
                        const col: number = +_col;
                        if (filePath === file) {
                            retVal.push({ file, line, col, id });
                        }
                    }
                }

return this.connection.TpServiceQuery({}).then(response => {
            const rootProtocol = this.connection.protocol();
            const ip = this.connection.ip();
            let port = rootProtocol === "https:" ? "18002" : "8002";
            if (exists("ServiceList.TpEspServers.TpEspServer", response)) {
                for (const item of response.ServiceList.TpEspServers.TpEspServer) {
                    if (exists("TpBindings.TpBinding", item)) {
                        for (const binding of item.TpBindings.TpBinding) {
                            if (binding.Service === type && binding.Protocol + ":" === rootProtocol) {
                                port = binding.Port;
                            }
                        }
                    }
                }
            }
            return `${rootProtocol}//${ip}:${port}/`;
        });
    }