Expressions

Overview

Expressions allow you to embed dynamic values in text components. They use the {{...}} delimiter syntax and are resolved at render time against the data context.

Syntax

Simple variables

Access top-level data properties by name:

{{title}}
{{invoiceNumber}}

Nested properties

Use dot notation to access nested objects:

{{customer.name}}
{{company.address.city}}

Function calls

Call built-in functions with arguments:

{{formatCurrency(price, 'USD')}}
{{formatDate(createdAt, 'yyyy-MM-dd')}}
{{uppercase(customer.name)}}

Mixed content

Expressions can appear anywhere in a text string alongside static text:

Invoice #{{invoiceNumber}} - {{formatDate(issueDate, 'MMMM d, yyyy')}}

Built-in functions

The engine provides 9 built-in functions for formatting and data manipulation:

Function	Arguments	Example	Result
formatCurrency	(value, currencyCode)	formatCurrency(1500, 'USD')	$1,500.00
formatDate	(value, pattern)	formatDate('2026-04-12', 'MMMM d, yyyy')	April 12, 2026
formatNumber	(value, decimals)	formatNumber(3.14159, 2)	3.14
sum	(array, property)	sum(items, 'price')	99.97
count	(array)	count(items)	3
uppercase	(value)	uppercase('hello')	HELLO
lowercase	(value)	lowercase('HELLO')	hello
concat	(value1, value2, ...)	concat('Hello', ' ', 'World')	Hello World
if	(condition, then, else)	if(total > 100, 'High', 'Low')	High or Low

formatCurrency

Formats a number as currency using the specified currency code and the report’s locale:

{{formatCurrency(item.price, 'USD')}}    → $29.99
{{formatCurrency(item.price, 'EUR')}}    → €29.99
{{formatCurrency(item.price, 'TRY')}}    → ₺29.99

formatDate

Formats a date string or Date object using a pattern:

{{formatDate(createdAt, 'yyyy-MM-dd')}}       → 2026-04-12
{{formatDate(createdAt, 'MMMM d, yyyy')}}     → April 12, 2026
{{formatDate(createdAt, 'dd/MM/yyyy')}}        → 12/04/2026

formatNumber

Formats a number with a specified number of decimal places:

{{formatNumber(3.14159, 2)}}   → 3.14
{{formatNumber(1000, 0)}}      → 1,000

sum

Calculates the sum of a numeric property across all elements in an array:

{{sum(items, 'price')}}    → 99.97
{{sum(items, 'quantity')}} → 42

count

Returns the number of elements in an array:

{{count(items)}}       → 3
{{count(employees)}}   → 12

uppercase / lowercase

Converts a string to upper or lower case:

{{uppercase(status)}}       → ACTIVE
{{lowercase(category)}}     → electronics

concat

Joins multiple values into a single string:

{{concat(firstName, ' ', lastName)}}   → John Smith

if

Conditional expression that returns one of two values:

{{if(total > 1000, 'Premium', 'Standard')}}
{{if(quantity > 0, formatCurrency(quantity * price, 'USD'), '-')}}

Type coercion

The expression engine provides helper functions for explicit type conversion:

Function	Description	Example
toNumber	Converts to number	toNumber('42') -> 42
toDate	Converts to Date	toDate('2026-04-12')
toBoolean	Converts to boolean	toBoolean(1) -> true
toString	Converts to string	toString(42) -> '42'

Expression context

Inside a detail band with dataBinding: 'items', the iterator variable (e.g., item) is added to the expression context. You can access both the iterator and top-level data:

{{item.name}}              → current item's name
{{customer.name}}          → top-level customer name
{{formatCurrency(item.price, currency)}}  → uses top-level currency code

Next steps

• Data Binding — how data flows into bands and components
• Components — where expressions are used
• Render API — render reports with data via the REST API