类型错误：超级表达式必须为空或函数 _inherits

Question

I am getting this error:

Super expression must either be null or a function

in the following code snippet:

import SQLite from 'react-native-sqlite-storage';
const DB = SQLite.openDatabase('Data.db');

class Database {
    db;
    constructor(db) {
        this.db = db;
    }
    executeSql = (sql, params = []) =>
        new Promise((resolve, reject) => {
            this.db.transaction((trans) => {
                trans.executeSql(
                    sql,
                    params,
                    (db, results) => {
                        resolve(results);
                    },
                    (error) => {
                        reject(error);
                    }
                );
            });
        });
}
export default new Database(DB);

import Database from '../db';
export class Note extends Database {
    constructor() {
        super();
    }

    all = () => async() => {
        console.log('all');
        const result = await DB.executeSql('Notes', ['params']);
        console.log('result', result);
    };
}

export default new Note();

Where is my mistake and how can I solve this problem?

Answer 1

Your mistake is that you are trying to create a Class ( Note ) that extends another Class ( Database ), but the imported Database object in the second file is not a Class, but an instantiated Class object.

You don't need to extend the Database, (and you can't, since it's not a Class). You just need to import and use the method directly.

import Database from '../db';
export class Note {

    constructor() {
    }

    all = () => async() => {
        console.log('all');
        const result = await Database.executeSql('Notes', ['params']);
        console.log('result', result);
    };
}

export default new Note();