> For the complete documentation index, see [llms.txt](https://lunes-labs.gitbook.io/dao-lunes-labs-pt/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://lunes-labs.gitbook.io/dao-lunes-labs-pt/developers/para-desenvolvedores/smart-contract-ink-4.x/frontend-development/hooks/contracts/usedryrun.md).

# useDryRun

A hook for calling a transaction as a dry run - a transction without spending any gas. Dry runs are useful to test if a transaction will be successful and for querying the exact Weight amount a transaction will need to succeed. This hook is used under the hood in [useTx](https://use.ink/frontend/core/hooks/contracts/use-tx), so you should only use this if you wish to display Dry Run information to the user before triggering a transaction.

See [useink/utils helpers](https://use.ink/frontend/utils/pick) for compatible functions that work well with this hook.

### Usage[​](https://use.ink/frontend/react/hooks/contracts/use-dry-run#usage) <a href="#usage" id="usage"></a>

```javascript
import { useDryRun, useContract } from 'useink'
import { pickTxInfo } from 'useink/utils'

export const MyContractView: React.FC = () => {
  const contract = useContract('...address', metadata, 'zeitgeist')
  
  const get = useDryRun<boolean>(contract, 'get')

  return (
    <>
      <button onClick={() => get.send()}>
        {get.isSubmitting ? 'Send Dry Run' : 'Sending...'}
      </div>

      <h2>Get the fee the hard way: {get.result.ok ? get.result.value.partialFee : '--'}</h2>
      <h2>Or the easy way: {pickTxInfo(get.result)?.partialFee || '--'}</h2>
    </>
  )
}
```

### Calling with a default caller address[​](https://use.ink/frontend/react/hooks/contracts/use-dry-run#calling-with-a-default-caller-address) <a href="#calling-with-a-default-caller-address" id="calling-with-a-default-caller-address"></a>

You must first define a default caller in [configuration](https://use.ink/frontend/configuration#configprops), then call the contract with options:

```javascript
const dryRun = useDryRun(cRococoContract, 'flip');
const args = [];

dryRun.send(args, { defaultCaller: true });
```

### Return Value[​](https://use.ink/frontend/react/hooks/contracts/use-dry-run#return-value) <a href="#return-value" id="return-value"></a>

```javascript
interface DryRun<T> {
  send: Send<T>;
  isSubmitting: boolean;
  result?: DryRunResult<T>;
  resolved: Boolean;
  resetState: () => void; // A convenience function to reset result state
}
```

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