const positionOffsetsService = new PositionOffsetsService(client);

positionOffsetsService.getAssetLoanAvailability({
    portfolio: 'PORTFOLIO_ID_HERE',
    asset: 'ETH',
}).then(async (response) => {
    console.log('Available Asset Loan: ', response);
})

For more information, please visit the INTX TS SDK.