MessageEmbed 字段值不能为空

Question

everytime I am trying to do like: ,help command, if the command doesn't have any aliases, it gives me that error in the console, I tried the following method which if there is no aliases for the specific command, it should return 'None': here's the code:

            let command = helpArgs[0]

            if(helpArgs[0]){
            if(bot.commands.has(command)) {
                command = bot.commands.get(command)
                const embed = new Discord.MessageEmbed()
                .setTitle(`${command.config.name}`)
                .addField('Name', `${command.config.name}`)
                .addField('Description', `${command.config.description}`)
                .addField('Usage', `${command.config.usage}`)
                .addField('Aliases', `${command.config.aliases !== undefined ? command.config.aliases : 'None'}`)
message.channel.send(embed)

And here is the error:

7:14 GMT+0300 (Eastern European Summer Time)
(node:11744) UnhandledPromiseRejectionWarning: RangeError [EMBED_FIELD_VALUE]: MessageEmbed field values may not be empty.
    at Function.normalizeField (C:\Users\\OneDrive\Documents\GitHub\Fergus\node_modules\discord.js\src\structures\MessageEmbed.js:425:23)
    at C:\Users\\OneDrive\Documents\GitHub\Fergus\node_modules\discord.js\src\structures\MessageEmbed.js:445:14
    at Array.map (<anonymous>)
    at Function.normalizeFields (C:\Users\\OneDrive\Documents\GitHub\Fergus\node_modules\discord.js\src\structures\MessageEmbed.js:444:8)
    at MessageEmbed.addFields (C:\Users\\OneDrive\Documents\GitHub\Fergus\node_modules\discord.js\src\structures\MessageEmbed.js:259:42) 
    at MessageEmbed.addField (C:\Users\\OneDrive\Documents\GitHub\Fergus\node_modules\discord.js\src\structures\MessageEmbed.js:250:17)  
    at Object.module.exports.run (C:\Users\\OneDrive\Documents\GitHub\Fergus\commands\Information\help.js:115:18)
    at processTicksAndRejections (internal/process/task_queues.js:97:5)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:11744) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:11744) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

The error is at.addField('Aliases', ${command.config.aliases?== undefined. command.config:aliases : 'None'} ), I checked each field.

Answer 1

I think the error may be, that the method you used in this field causes an error and because of this, the field is empty. To list the aliases in a string you can try the following method.

let aliases = command.config.aliases.toString();
if (aliases == "") {
    aliases = "None";
}


.addField('Aliases', `${aliases}`)

With this method, you create a String from the aliases array of your command config. Then you look if there aren't any aliases. If yes the String is "None". After this, you need to replace your method in the embed with the variable aliases .

Answer 2

It seems like command.config.aliases is indeed empty, even though it is not undefined. You should modify the check. I do not know what the aliases field contains, so I cannot say what the check should be.