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Using Super Commands with the Flow CLI

Flow CLI Super commands are set of commands that can be used during development of your dApp to greatly simplify the workflow. The result is you can focus on writing the contracts and the commands will take care of the rest.

Setup​

The initial command to start your new Flow project is flow setup . By default, it will create basic folder structure and a flow.json configuration.

Running the command:


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> flow setup

Will create the following folders and files:

  • /contracts folder should contain all your Cadence contracts,
  • /scripts folder should contain all your Cadence scripts,
  • /transactions folder should contain all your Cadence transactions,
  • /tests folder should contain all your Cadence tests,
  • flow.json is a configuration file for your project, which will be automatically maintained.

Using Scaffolds​

Based on the purpose of your project you can select from a list of available scaffolds. You can access the scaffolds by simply using the --scaffold flag like so:


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> flow setup --scaffold

The list of scaffolds will continuously grow, and you are welcome to contribute to that. You can contribute by creating your own scaffold repository which can then be added to the scaffold list by following instructions here.

Develop​

After creating the project using the flow setup command you can start the emulator in the project directory by running flow emulator. After emulator is started up you can continue by running the flow develop command like so:


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> flow dev

This will continuously watch for your projects Cadence files for changes and keep them in sync with the deployed contracts on the emulator.

The output will look something like:


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[15:53:38] Syncing all the contracts...
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😜 charlie
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|- MyContract contracts/charlie/MyContract.cdc
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😏 emulator-account
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|- HelloWorld contracts/HelloWorld.cdc

After the command is started it will automatically watch any changes you make to Cadence files and make sure to continuously sync those changes on the emulator network. If you make any mistakes it will report the errors as well.

It is recommended that you use VSCode as the IDE and run the command in the terminal window of the IDE. The latest VSCode extension also supports resolution of the improved import syntax, more on that later.

⚠️ Please note that this command only works on the emulator network. It's meant for development only and hence it doesn't allow interacting with testnet or mainnet network. After your project is completed you will be soon able to migrate it using a migration super command. Also, please note the command requires a running emulator which you have to start. If you restart the emulator the command needs to be restarted as well. This command is meant to be used during development, and it updates the contracts by removing and redeploying them, which means that if you manually interacted with those contracts and stored resources in accounts storage that stored items might no longer be valid after contract is updated. Our advise is to first focus on development and use automated tests to assert correct functionality and interact with contracts manually after this cycle is complete. Also note that this is still a very experimental feature, so it might undergo a lot of changes and improvements as we learn from the usage.

Deploying Contracts

When adding the contracts to the /contracts folder it will automatically deploy them to the default account, which is also created for you at startup of running flow dev.

If you want to add the contracts to a separate account all you have to do is create a folder inside the /contracts folder and add the contract there, that will first automatically create the account with the same name as the folder name and then deploy all the contracts inside that folder to that newly created account.

Example: If I want to have a contract named A.cdc deployed to a default account and a contract named B.cdc deployed to account called Bob my folder structure inside contracts folder will look like:


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/contracts
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A.cdc
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bob/
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B.cdc

Import Schema​

In order to simplify your workflow we have introduced a new way to import your contracts during development. You can simply import them by their name.

The new import schema format looks like:


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import "{name of the contract}"

Example:


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import "HelloWorld"

This will automatically import the contract you have created in your project with the same name and save the configuration in flow.json. It doesn't matter if the contract is deployed on a non-default account.