zkoss/zk

/* preferStrictBooleanType.ts

    Purpose:
        
    Description:
        
    History:
        2:09 PM 2022/7/26, Created by jumperchen

Copyright (C) 2022 Potix Corporation. All Rights Reserved.
*/
import { AST_NODE_TYPES, TSESTree } from '@typescript-eslint/utils';
import { createRule } from '../util';

export const preferStrictBooleanType = createRule({
    name: 'preferStrictBooleanType',
    meta: {
        type: 'problem',
        docs: {
            description: 'Prefer boolean type only.',
            recommended: 'error',
        },
        fixable: 'code',
        messages: {
            useBooleanTypeOnly: 'Use boolean type only.',
        },
        schema: []
    },
    defaultOptions: [],
    create(context) {
        function checkBooleanTypeSyntax(node: TSESTree.TSTypeAnnotation | TSESTree.TSTypeAssertion | TSESTree.TSAsExpression) {
            if (node.typeAnnotation.type === AST_NODE_TYPES.TSUnionType) {
                let booleanType:  TSESTree.TSBooleanKeyword | null | undefined;
                for (const t of node.typeAnnotation.types) {
                    if (t.type === AST_NODE_TYPES.TSBooleanKeyword) {
                        if (booleanType !== null) {
                            booleanType = t;
                        }
                    } else if (t.type !== AST_NODE_TYPES.TSNullKeyword &&
                        t.type !== AST_NODE_TYPES.TSUndefinedKeyword) {
                        booleanType = null;
                    }
                }

                if (booleanType) {
                    context.report({
                        node: booleanType,
                        messageId: 'useBooleanTypeOnly',
                        fix(_fixer) {
                            return {
                                range: node.typeAnnotation.range,
                                text: 'boolean'
                            } as never;
                        }
                    });
                }
            }
        }
        return {
            TSTypeAnnotation: checkBooleanTypeSyntax,
            TSTypeAssertion: checkBooleanTypeSyntax,
            TSAsExpression: checkBooleanTypeSyntax
        };
    }
});