Cannot read properties of null.

const { SlashCommandBuilder, PermissionsBitField, EmbedBuilder } = require('discord.js');
const warningSchema = require('../../Schemas/warnSchema');

module.exports = {
    data: new SlashCommandBuilder()
    .setName('warn')
    .setDescription('Warns a user.')
    .addUserOption(option => option
        .setName('user')
        .setDescription('Username of who you want to warn.')
        .setRequired(true)
        )
    .addStringOption( option => option
        .setName('reason')
        .setDescription('Reason for warning the User.')
        .setRequired(false)
    ),
    async execute(interaction) {
        if(
            !interaction.member.permissions.has(PermissionsBitField.Flags.KickMembers)
        ) return await interaction.reply(
            {content: "Sorry! You don't have the sufficient permissions required to run this command!", ephemeral: true}
        )

        const {options, guildId, user} = interaction;

        const target = options.getUser('user');
        const reason = options.getString('reason') || "No reason provided!"
        const userTAG = `${target.username}`

        warningSchema.findOne({GuildID: guildId, UserID: target.id, Username: target.tag}, async(err, data) => {
            if(err) throw err;
            if(data) {
                data = new warningSchema({
                    GuildID: guildId,
                    UserID: target.id,
                    Username: userTAG,
                    Content: [
                        {
                            Executor: target.tag,
                            ExecutorID: user.id,
                            Reasom: reason
                        }
                    ],
                });

            } else {
                const warnContent = {
                    Executor: target.tag,
                    ExecutorID: user.id,
                    Reasom: reason
                };
                 
            data.Content.push(warnContent)
            }
            data.save()
        });

        const embed = new EmbedBuilder()
        .setColor('#5077B4')
        .setTitle('New Warning.')
        .setDescription(`:white_check_mark: You have recieved a warning in ${interaction.guild.name} || ${reason}`)

        const embed2 = new EmbedBuilder()
        .setColor('#5077B4')
        .setTitle('New Warning.')
        .setDescription(`:white_check_mark: Succesfully warned ${target.tag} || ${reason}`)

        target.send({ embeds: [embed] }).catch(err => {
            return;
        })

        interaction.reply({ embeds: [embed2] })
    }
}

const { SlashCommandBuilder, PermissionsBitField, EmbedBuilder } = require('discord.js');
const warningSchema = require('../../Schemas/warnSchema');

module.exports = {
    data: new SlashCommandBuilder()
    .setName('warn')
    .setDescription('Warns a user.')
    .addUserOption(option => option
        .setName('user')
        .setDescription('Username of who you want to warn.')
        .setRequired(true)
        )
    .addStringOption( option => option
        .setName('reason')
        .setDescription('Reason for warning the User.')
        .setRequired(false)
    ),
    async execute(interaction) {
        if(
            !interaction.member.permissions.has(PermissionsBitField.Flags.KickMembers)
        ) return await interaction.reply(
            {content: "Sorry! You don't have the sufficient permissions required to run this command!", ephemeral: true}
        )

        const {options, guildId, user} = interaction;

        const target = options.getUser('user');
        const reason = options.getString('reason') || "No reason provided!"
        const userTAG = `${target.username}`

        warningSchema.findOne({GuildID: guildId, UserID: target.id, Username: target.tag}, async(err, data) => {
            if(err) throw err;
            if(data) {
                data = new warningSchema({
                    GuildID: guildId,
                    UserID: target.id,
                    Username: userTAG,
                    Content: [
                        {
                            Executor: target.tag,
                            ExecutorID: user.id,
                            Reasom: reason
                        }
                    ],
                });

            } else {
                const warnContent = {
                    Executor: target.tag,
                    ExecutorID: user.id,
                    Reasom: reason
                };
                 
            data.Content.push(warnContent)
            }
            data.save()
        });

        const embed = new EmbedBuilder()
        .setColor('#5077B4')
        .setTitle('New Warning.')
        .setDescription(`:white_check_mark: You have recieved a warning in ${interaction.guild.name} || ${reason}`)

        const embed2 = new EmbedBuilder()
        .setColor('#5077B4')
        .setTitle('New Warning.')
        .setDescription(`:white_check_mark: Succesfully warned ${target.tag} || ${reason}`)

        target.send({ embeds: [embed] }).catch(err => {
            return;
        })

        interaction.reply({ embeds: [embed2] })
    }
}