Enforce Data Validation on Models in Sequelize

In addition to constraints, Sequelize provides a list of built-in model validators implemented by the validator library, that allow you check and validate the data format of columns through the validate property:

{
  <column>: {
    type: <type>,
    validate: {
      <validator>: <value>,
      ...
    }
  }
}

Note: These validators are only executed upon CREATE and UPDATE operations.

Validate numbers

To check numbers, you can use:

• isNumeric: true: to only allow numbers.
• isInt: true: to check for valid integers.
• isFloat: true: to check for floating point numbers.
• isDecimal: true: to check for any numbers.
• max: <number>: to only allow values <= number.
• min: <number>: to only allow values >= number.

Example

For example:

{
  latitude: {
    type: DataTypes.FLOAT,
    validate: {
      isDecimal: true,
      min: -90,
      max: 90
    }
  }
}

Validate strings

To check strings, you can use:

• isAlpha: true: to only allow letters.
• isAlphanumeric: true: to only allow letters and digits.
• isLowercase: true: to check for lowercase letters.
• isUppercase: true: to check for uppercase letters.
• notEmpty: true: to not allow empty strings.
• contains: <string>: to check for a substring.
• notContains: <string>: to not allow a substring.
• len: [<number>,<number>]: to only allow length between values.

Example

For example:

{
  pseudo: {
    type: DataTypes.STRING(20),
    validate: {
      isAlphanumeric: true,
      isLowercase: true,
      notEmpty: true,
      len: [6, 20]
    }
  }
}

Validate regular expressions

To match a field against a regular expression, you can use:

• is: /pattern/: to check if the field matches a pattern.
• not: /pattern/: to check if the field doesn't match a pattern.

Example

For example:

{
  name: {
    type: DataTypes.STRING(50),
    validate: {
      is: /^([a-zA-Z-]+\s)?$/i
    }
  }
}

Validate common expressions

To check common expressions, such as email addresses or URLs, you can use:

• isEmail: true: to check email addresses.
• isUrl: true: to check URLs.
• isIP: true: to check IPv4 or IPv6 addresses.

Example

For example:

{
  email: {
    type: DataTypes.STRING(320),
    validate: {
      isEmail: true
    }
  }
}

Validate dates

To check dates, you can use:

• isDate: true: to only allow date strings.
• isAfter: "2011-11-05": to only allow date strings after a specific date.
• isBefore: "2011-11-05": to only allow date strings before a specific date.

Example

For example:

{
  start_date: {
    type: DataTypes.DATEONLY,
    validate: {
      isAfter: '2025-01-01'
    }
  }
}

Validate exact values

To check exact values, you can use:

• isIn: [['foo', 'bar']]: to check if the value is one of these.
• notIn: [['foo', 'bar']]: to check the value is not one of these.
• equals: 'value': to only allow a specific value.

Example

For example:

{
  genre: {
    type: DataTypes.STRING,
    validate: {
      isIn: [['Action', 'Comedy', 'Drama', 'Horror']]
    }
  }
}