Checking disallowed words inside fs.appendFile block. (logger node.js)

  constructor(directory, wordsToIgnore) {
        super();
        this.directory = directory;
        this.wordsToIgnore = wordsToIgnore;
    }

    log(message) {
        const passedValidation = !this.wordsToIgnore.includes(message);
        var today = new Date();
        let logDate = `${today.getFullYear()}-${today.getMonth()}-${today.getDate()}.txt`;
        fs.appendFile(this.directory + logDate, `${message}\n`, 'utf8',
            err => {
                if (err) {
                    this.emit('reject', `${message} has not been logged , reason: ${err.code}`);
                }
                else {
                    this.emit('success', `${message} has been load`);
                }
            });
    }

this is my code. i suppose to check if message contains one of the “wordsIgnore” array words. how could i manage to make the “if statment” to check it … i added if statment but it still appending the disallowed words . thank you for help guys .!