I'm doing a schema with mongoose in Nodejs. And I'm trying to find a way to limit the number of character in a SchemaString. I found that it is possible to use a regex with the keyword match like :

var schema = new Schema({
{
    name: {type: String, match: '/^.{0,20}$/'}
});

But I just want to know if there is some parameter to directly specify a maximum length, like this :

var schema = new Schema({
{
    name: {type: String, max: 20}
});

Thank you for your help.

Since Mongoose 4.0.0-rc2, the maxLength validation is available:

var Schema = new mongoose.Schema({
  name: {type: String, required: true, maxLength: 20}
});

For versions older than 4.0.0-rc2, there is no such validation built in.

You can however create this validation using path function:

Schema.path('name').validate(function (v) {
    return v.length <= 20;
}, 'The maximum length is 20.');

Or you can use mongoose-validator. From the example in their README:

var mongoose = require('mongoose');
var validate = require('mongoose-validator');

var nameValidator = [
  validate({
    validator: 'isLength',
    arguments: [3, 50],
    message: 'Name should be between 3 and 50 characters'
  }),
  validate({
    validator: 'isAlphanumeric',
    passIfEmpty: true,
    message: 'Name should contain alpha-numeric characters only'
  })
];

var Schema = new mongoose.Schema({
  name: {type: String, required: true, validate: nameValidator}
});