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Scalar Types

Scalar types are the primitive data types that can be used to define the schema of the GraphQL application. Slicknode supports a variety of scalar types:

String

The String type is for storing text values.

Example usage:

type NewsFeed_Article implements Node {
  id: ID!
  text: String
}

Configure Input Element:

There are multiple input elements available in the Slicknode console. By default, the console interface creates a single line input element of type text for all String fields.

If you need multi line input or want to use markdown etc. you can customize the input widget by adding the @input directive to the field:

type NewsFeed_Article implements Node {
  id: ID!

  # Use a Markdown editor
  text: String @input(type: MARKDOWN)

  # Use a password input for this value
  secretValue: String @input(type: PASSWORD)

  # Use plain multiline textarea input
  multilineText: String @input(type: TEXTAREA)
}

Int

The Int type is for storing numeric values. This is as per the GraphQL specification a 32 bit integer.

Limitations
Maximum value	2147483647
Minimum value	-2147483648

If you need to store values that are out of the range of a 32 bit integer, use the Decimal type.

Example usage:

type NewsFeed_Article implements Node {
  id: ID!
  visits: Int
}

Float

The Float type is for storing floating point numbers.

Example usage:

type NewsFeed_Article implements Node {
  id: ID!
  rating: Float!
}

Warning

Do not use this data type to store exact values like money amounts, as aggregations and calculations on floating point numbers can lead to inaccuracies. If you need exact values, use the Decimal scalar instead.

Boolean

The Boolean type is for storing boolean values (true / false).

Example usage:

type NewsFeed_Article implements Node {
  id: ID!
  published: Boolean!
}

DateTime

The DateTime type can be used to store ISO 8601 date time values with timezone and milliseconds precision.

Example values:

# Datetime + timezone
2018-01-11T14:38:30+02:00

# UTC Date
2018-01-11T14:38:30Z

# UTC Datetime + timezone with milliseconds 
2017-12-27T22:25:21.830Z

ID

The ID scalar is for storing unique identifiers of nodes. The type is reserved for object types that implement the Node interface and can only be used for the field id. If you need to store identifiers of other systems, use a String scalar instead.

Example usage:

type NewsFeed_Article implements Node {
  id: ID!
}

Decimal

The Decimal scalar can be used to store large numbers or decimal numbers where exact values are important (e.g. monetary values). It is slower and requires more storage in the database, but can handle larger numbers than the Int or Float scalars.

Limitations
Maximum digits	1000 decimal digits on both sides of the decimal point combined. (e.g: -12.345 would count as 5 digits)
Maximum value	A decimal value with 1000 digits
Minimum value	A negative value with 1000 digits

Important

The values are always returned as a String value. For example "-4.0567". If you want to do further calculations in the client, you would first have to convert this value into a data type on which you can perform numeric operations. Always make sure that your programming language can handle the maximum and minimum values that can be returned by your GraphQL endpoint.

Example: Large integers in Javascript

If you use the Decimal scalar to store numbers that are larger than 32 bit and can't be stored as Int, you can use the parseInt function to convert the returned Decimal to an integer. However, Javascript does have a limit of 53 bit for integers. You can only do this if you can be sure that your numbers never exceed 9,007,199,254,740,991 (2^53 - 1) and -9,007,199,254,740,991 (-2^53 - 1).

// Convert decimal value to integer
const numericValue = parseInt(decimalValue, 10);

If you need to process larger numbers than that, use a library like big-int

Example: Floating point numbers in Javascript

To convert Decimal values to floating point numbers, you can use the javascript function parseFloat. Keep in mind that the resulting values come with the inaccuracies of floating point numbers and that the values might be rounded depending on the floating number limitation of the language and operating system.

// Convert decimal value to floating point number
const floatNumber = parseFloat(decimalValue);

If you need to handle accurate numbers with arbitrary precision, use a library like bigdecimal