Style Rules

Core style rules check structure and naming in every chant project, whatever the lexicon.

---

COR001: Inline Object in Constructor

Resource constructor properties must not contain inline object literals or arrays-of-objects. Each config value should be its own named, exported const.

Severity: warning

// ❌ Triggers COR001
export const bucket = new _.Bucket({
  bucketEncryption: {
    serverSideEncryptionConfiguration: [
      { serverSideEncryptionByDefault: { sseAlgorithm: "AES256" } },
    ],
  },
});

// ✅ Fixed — extract each config value
export const encryptionDefault = new _.ServerSideEncryptionByDefault({
  sseAlgorithm: "AES256",
});

export const encryptionRule = new _.ServerSideEncryptionRule({
  serverSideEncryptionByDefault: encryptionDefault,
});

export const bucketEncryption = new _.BucketEncryption({
  serverSideEncryptionConfiguration: [encryptionRule],
});

export const bucket = new _.Bucket({
  bucketEncryption: bucketEncryption,
});

Simple string, number, and boolean properties are allowed inline. Only nested object literals and arrays containing objects are flagged.

The rule looks only at resource constructors. A property-kind declarable is one a lexicon builds with createProperty and lists in its plugin’s propertyClassNames(). It is already a nested value inside the resource that holds it, so the objects passed to it are not flagged. Grafana declares its panel classes this way, so a panel can carry its fieldConfig and options inline.

// OK: TimeSeriesPanel is property-kind
export const overview = new Dashboard({
  title: "Overview",
  panels: [
    new TimeSeriesPanel({ title: "Latency", fieldConfig: { defaults: { unit: "ms" } } }),
  ],
});

A lexicon that does not implement propertyClassNames() gets the rule on every constructor, as before.

Note

This rule skips Composite() factory callbacks, where inline construction is expected. See Composite Rules.

---

COR005: Naming Convention

Exported declarable instances should use camelCase naming. PascalCase and UPPER_SNAKE_CASE are reserved for types and constants.

Severity: warning

// ❌ Triggers COR005
export const DataBucket = new _.Bucket({
  bucketName: "my-data",
});

export const DATA_BUCKET = new _.Bucket({
  bucketName: "my-data",
});

// ✅ Fixed
export const dataBucket = new _.Bucket({
  bucketName: "my-data",
});

Only applies to exported variables initialized with new expressions.

---

COR009: File Declarable Limit

A file may hold up to 8 resource declarations by default.

Only resources count. The classes a lexicon lists in its plugin’s propertyClassNames() are property-kind and are left out. A Grafana dashboard file with twenty panels inside one dashboard counts as one declarable. A lexicon that does not implement propertyClassNames() has every declarable counted, as before.

Severity: warning

⚠ COR009: File contains 12 Declarable instances (limit: 8) — consider splitting into separate files by concern

Fix: Split the file by concern. For example, separate networking resources from compute resources.

Configure the limit:

chant.config.ts

export default {
  lint: {
    rules: {
      COR009: ["warning", { max: 12 }],
    },
  },
};

---

COR012: Redundant Type Import

When a namespace import already exists for a package, a separate import type from the same package is redundant.

Severity: warning

// ❌ Triggers COR012
import { isDeclarable } from "@intentius/chant";
import type { Declarable } from "@intentius/chant";

// ✅ Fixed — import the type as a named import
import { isDeclarable, type Declarable } from "@intentius/chant";

const d: Declarable = /* ... */;

chant lint --fix removes the redundant import type line.

---

COR013: Single-Concern File

Keep resources (e.g., Bucket, Function, Role) and properties (e.g., BucketEncryption, VersioningConfiguration, PublicAccessBlockConfiguration) in separate files.

Severity: info

// ❌ Triggers COR013 — mixes resource and configuration
export const encryptionDefault = new _.ServerSideEncryptionByDefault({
  sseAlgorithm: "AES256",
});

export const bucket = new _.Bucket({
  bucketEncryption: _.bucketEncryption,
});

Fix: Move configuration declarations to a defaults.ts file and resources to their own files.

---

COR015: Redundant Value Cast

AttrRef and other intrinsic types already satisfy Value<T>, so casting with as Value<...> is redundant.

Severity: warning

// ❌ Triggers COR015
export const fn = new _.Function({
  role: functionRole.arn as Value<string>,
});

// ✅ Fixed — use directly without cast
export const fn = new _.Function({
  role: functionRole.arn,
});