Fields

Represents the custom fields that are used in an issue. The actual set of custom fields that are used for each issue is configured on a per-project basis. The properties shown here correspond with the default custom fields in YouTrack. Additional custom fields that have been attached to a project are also available.

Methods

becomes

static becomes(field, expected)

Checks whether the value for a custom field is set to an expected value in the current transaction.

Parameters

Name	Type	Description
field	string, ProjectCustomField	The field to check.
expected	Object	The expected value.

Return Value

Type	Description
boolean	If the field is set to the expected value, returns `true`.

canBeReadBy

static canBeReadBy(field, user)

Checks whether a user has permission to read the custom field.

Parameters

Name	Type	Description
field	string, ProjectCustomField	The custom field to check for read access.
user	User	The user for whom the permission to read the custom field is checked.

Return Value

Type	Description
boolean	If the user can read the field, returns `true`.

canBeWrittenBy

static canBeWrittenBy(field, user)

Checks whether a user has permission to update the custom field.

Parameters

Name	Type	Description
field	string, ProjectCustomField	The custom field to check for update access.
user	User	The user for whom the permission to update the custom field is checked.

Return Value

Type	Description
boolean	If the user can update the field, returns `true`.

isChanged

static isChanged(field)

Checks whether the custom field is changed in the current transaction.

Parameters

Name	Type	Description
field	string, ProjectCustomField	The name of the custom field (for example, 'State') or a reference to the field that is checked.

Return Value

Type	Description
boolean	If the value of the field is changed in the current transaction, returns `true`.

oldValue

static oldValue(field)

Returns the previous value of a single-valued custom field before an update was applied. If the field is not changed in the transaction, returns null.

Parameters

Name	Type	Description
field	string, ProjectCustomField	The name of the custom field (for example, 'State') or a reference to the field for which the previous value is returned.

Return Value

Type	Description
Object	If the custom field is changed in the current transaction, the previous value of the field. Otherwise, the current value of the field.

required

static required(fieldName, message)

Asserts that a value is set for a custom field. If a value for the required field is not set, the specified message is displayed in the user interface.

Parameters

Name	Type	Description
fieldName	string	The name of the custom field to check.
message	string	The message that is displayed to the user that describes the field requirement.

10 September 2026