Automatically transform Mongoose validation error message(s) to a humanized and readable format, built for CrocodileJS.

• Install
• Usage
• License

npm install --save mongoose-validation-error-transform

You may also want to use mongoose-beautiful-unique-validation too (see this comment)!

const mongooseValidationErrorTransform = require('mongoose-validation-error-transform');

mongoose.plugin(mongooseValidationErrorTransform, {

  //
  // these are the default options you can override
  // (you don't need to specify this object otherwise)
  //

  // should we capitalize the first letter of the message?
  capitalize: true,

  // should we convert `full_name` => `Full name`?
  humanize: true,

  // how should we join together multiple validation errors?
  transform: function(messages) {
    return messages.join(', ');
  }

});

If you have a Mongoose schema defined with a required String field full_name, and if there is an error with a missing full_name on a document - then it will automatically rewrite the message of full_name is required to Full name is required.

If there are multiple validation error messages, such as:

• full_name is required
• age is not at least (18)

Then it will rewrite the error message to Full name is required, Age is not at least (18).

Of course - by modifying the options mentioned above, you can transform the messages however you'd like.

For example, if you'd like to output a <ul> HTML tag with <li> for each error (but only of course if there's more than one error):

mongoose.plugin(mongooseValidationErrorTransform, {
  transform: function(messages) {
    if (messages.length === 1) return messages[0];
    return `<ul><li>${messages.join('</li><li>')}</li></ul>`;
  }
});

This would output the following for the previous example:

<ul><li>Full name is required</li><li>Age is not at least (18)</li></ul>

MIT © Nick Baugh