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Reserved Words in Envio

Overview​

A few names can't be used for contracts, events, entities or enums, because the code Envio generates looks them up on plain JavaScript objects. Using one makes codegen fail before the indexer starts.

Since v3.9 the list is short. JavaScript, TypeScript and ReScript keywords such as class, interface or type are allowed, because Envio capitalizes the identifiers it generates. Before v3.9, those keywords were reserved too.

Reserved Names​

These names are reserved for contract and event names in config.yaml, and for entity names, enum names and enum values in schema.graphql:

__defineGetter__, __defineSetter__, __lookupGetter__, __lookupSetter__,
__proto__, constructor, hasOwnProperty, isPrototypeOf,
propertyIsEnumerable, toLocaleString, toString, valueOf, enum

The first twelve are the properties every JavaScript object inherits from Object.prototype. enum is reserved because entities are re-exported from the envio module under their capitalized names, where Enum is already taken.

Other Naming Rules​

  • Contract and event names must contain only letters, digits and underscores, and can't start with a digit.
  • Entity fields can't map to a database column starting with envio_, which is reserved for internal columns.
  • With per-chain entities, the field names chainId and chain_id are reserved for the chain column.

Error Messages​

A reserved name in config.yaml:

The config contains reserved words for contract names: "valueOf". They are used for the generated code and must be valid identifiers, containing only alphanumeric characters and underscores.

The same message names event instead of contract for an event name. A reserved name in schema.graphql:

Schema contains the following reserved keywords: toString

How to Fix Reserved Word Errors​

  1. Rename the identifiers listed in the error.
  2. Update every reference to them in your handlers and tests.
  3. Run pnpm codegen to check the result.

Example​

# config.yaml
contracts:
  - name: valueOf # Error: reserved
    abi_file_path: ./abis/MyContract.json
# Fixed config.yaml
contracts:
  - name: ValueOracle # Good: not reserved
    abi_file_path: ./abis/MyContract.json

If you encounter persistent issues with reserved words or need help refactoring your schema to avoid them, please reach out for support on our Discord community.