SAP Fiori Input Masks with Regular Expression Validation

Hello Everyone! 👋

A new CDS annotation, @UI.inputMask, allows you to define input masks and regular expression validations directly in SAP Fiori applications.

We often come across scenarios where a field value must follow a specific format, such as SWIFT codes, reference numbers, or other business-specific identifiers. Traditionally, this requires custom validation logic to validate prefixes, character types, and overall patterns.

With @UI.inputMask, these requirements can be handled directly at the UI level, improving user guidance and reducing the need for custom validation logic.

Note:

• As of now, @UI.inputMask is available in the latest verison of SAP S/4HANA Public Cloud and the ABAP Environment (Steampunk/BTP ABAP Environment).
• The mask is applied only at the UI layer for input guidance, validation, and display purposes.
• The underlying data is stored and transferred without the mask formatting characters. The mask does not change the actual value persisted in the database.
• As of now, dynamic masks are not supported; the mask must be defined statically in the annotation.

Example 1: Standard Mask

@UI.inputMask: {
  mask: 'AAAA-AA-XX-XXX',
  placeholderSymbol: '_',
  rules: [
    { maskSymbol: 'X', regularExpression: '[a-zA-Z0-9]' },
    { maskSymbol: 'A', regularExpression: '[a-zA-Z]' }
  ]
}
fieldname;

Result

____-__-__-___

Valid Input

ABCD-EF-A1-B2C

Where:

• A accepts only alphabetic characters (A-Z, a-z)
• X accepts alphanumeric characters (A-Z, a-z, 0-9)

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Example 2: Fixed Prefix

@UI.inputMask: {
  mask: 'CONST-AA-XX-XXX',
  placeholderSymbol: '_',
  rules: [
    { maskSymbol: 'X', regularExpression: '[a-zA-Z0-9]' },
    { maskSymbol: 'A', regularExpression: '[a-zA-Z]' }
  ]
}
fieldname;

Result

CONST-__-__-___

Valid Input

CONST-AB-C1-D2E

Since CONST is not part of any rule, it is treated as a fixed literal value and displayed automatically.

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Example 3: Escaping a Mask Symbol

@UI.inputMask: {
  mask: 'C^AR-AA-XX-XXX',
  placeholderSymbol: '_',
  rules: [
    { maskSymbol: 'X', regularExpression: '[a-zA-Z0-9]' },
    { maskSymbol: 'A', regularExpression: '[a-zA-Z]' }
  ]
}
fieldname;

Result

CAR-__-__-___

Valid Input

CAR-AB-C1-D2E

In this example, A is defined as a mask symbol. By using the escape character (^), the A in CAR is treated as a literal character rather than a mask placeholder.

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