Allow functions with certain names

[michaeljota]

Description

In Angular, factories should be named functions, as you can read here angular/angular#13702 and here angular/angular#13614. Because of that, this rule interferes and throws when a factory is needed to be used.

@NgModule({
  providers: [
    {
      provide: APOLLO_OPTIONS,
      useFactory(httpLink: HttpLink): ApolloClientOptions<any> { // <-- Throws
        return {
          link: httpLink.create({ uri }),
          cache: new InMemoryCache(),
        };
      },
      deps: [HttpLink],
    },
  ],
})
export class GraphQLModule {}

export function createApollo(httpLink: HttpLink): ApolloClientOptions<any> { // <--- Also throws
  return {
    link: httpLink.create({ uri }),
    cache: new InMemoryCache(),
  };
}

Suggested Solution

Adding an option that allows us to add patterns to ignore would be helpful because then we would only need to come up with a standard name for factories in the project.

Help Needed

[Samuel-Therrien-Beslogic]

For now I disable this config in component files:

    {
      files: ["*.component.ts"],
      rules: {
        // Factories (including lifecycles) should be named functions
        "extra-rules/potential-point-free": "warn",
        "prefer-arrow/prefer-arrow-functions": [
          "error",
          {
            ...preferArrowFunctionsConfig,
            "singleReturnOnly": true,
          },
        ],
      },
    },

[JamieMason]

Hi @michaeljota @Samuel-Beslogic,
This should be possible by modifying isSafeTransformation to return false if the name matches one of the ones you want to ignore:

eslint-plugin-prefer-arrow-functions/src/prefer-arrow-functions.ts

Lines 203 to 214 in 4520ba6

	const isSafeTransformation = (node) => {
	return (
	!isGeneratorFunction(node) &&
	!containsThis(node) &&
	!containsSuper(node) &&
	!containsArguments(node) &&
	!containsNewDotTarget(node) &&
	(!isPrototypeAssignment(node) || disallowPrototype) &&
	(!singleReturnOnly ||
	(returnsImmediately(node) && !isNamedDefaultExport(node)))
	);
	};

There is a `getFunctionName function

eslint-plugin-prefer-arrow-functions/src/prefer-arrow-functions.ts

Lines 80 to 81 in 4520ba6

	const getFunctionName = (node) =>
	node && node.id && node.id.name ? node.id.name : '';

Adding a new option of names to ignore gets read here

eslint-plugin-prefer-arrow-functions/src/prefer-arrow-functions.ts

Lines 35 to 43 in 4520ba6

	const options = context.options[0] || {};
	const getOption = (name) =>
	typeof options[name] !== 'undefined'
	? options[name]
	: DEFAULT_OPTIONS[name];
	const singleReturnOnly = getOption('singleReturnOnly');
	const classPropertiesAllowed = getOption('classPropertiesAllowed');
	const disallowPrototype = getOption('disallowPrototype');
	const returnStyle = getOption('returnStyle');

And the new value will also want adding the ESLint's schema

eslint-plugin-prefer-arrow-functions/src/prefer-arrow-functions.ts

Lines 17 to 32 in 4520ba6

	schema: [
	{
	additionalProperties: false,
	properties: {
	classPropertiesAllowed: { type: 'boolean' },
	disallowPrototype: { type: 'boolean' },
	returnStyle: {
	default: DEFAULT_OPTIONS.returnStyle,
	pattern: '^(explicit|implicit|unchanged)$',
	type: 'string',
	},
	singleReturnOnly: { type: 'boolean' },
	},
	type: 'object',
	},
	],

Thanks a lot.