one-contract-per-file

Enforces that a file contains at most one contract/interface/library definition.

Rule details

Examples of incorrect code for this rule:

contract A {}
contract B {}

Examples of correct code for this rule:

contract A {}

Options

The rule can be configured to allow multiple contracts/interfaces/libraries in a single file by specifying an allow option in the configuration. The allow option is an array of objects, each specifying the maximum number of each type of definition allowed in the file.

For example, to allow one contract and one interface in a file, you can do:

"one-contract-per-file": [
  "error",
  {
    "allow": [
      {
        "contracts": 1,
        "interfaces": 1
      }
    ]
  }
]