Operators

The expression engine supports arithmetic, comparison, and logical operators.

Arithmetic operators

Operator	Description	Example	Result
`+`	Addition / string concatenation	`{{price + tax}}`	`110`
`-`	Subtraction	`{{total - discount}}`	`90`
`*`	Multiplication	`{{price * quantity}}`	`50`
`/`	Division	`{{total / count}}`	`25`
`%`	Modulo (remainder)	`{{index % 2}}`	`0` or `1`
`**`	Exponentiation	`{{base ** 2}}`	`9`

String concatenation with `+`

When either operand is a string, + performs concatenation:


{{firstName + " " + lastName}}    → "Alice Smith"
{{"ID-" + id}}                    → "ID-42"

Comparison operators

Operator	Description	Example	Result
`==`	Strict equality	`{{status == "active"}}`	`true` or `false`
`===`	Strict equality	`{{status === "active"}}`	`true` or `false`
`!=`	Strict inequality	`{{type != "admin"}}`	`true` or `false`
`!==`	Strict inequality	`{{type !== "admin"}}`	`true` or `false`
`>`	Greater than	`{{age > 18}}`	`true` or `false`
`<`	Less than	`{{price < 100}}`	`true` or `false`
`>=`	Greater than or equal	`{{age >= 21}}`	`true` or `false`
`<=`	Less than or equal	`{{score <= 50}}`	`true` or `false`

Both == and === use strict equality. There is no loose equality — == behaves identically to ===. Similarly, != and !== both use strict inequality. This is a deliberate safety choice.

String literals in comparisons

When comparing against a string literal on the right side, the literal is treated as a value, not as a field name.


{ "status": "active", "active": true }


{{status == "active"}}     → true   (compares status field to string "active")
{{status == active}}       → false  (compares "active" to boolean true)

This means "active" on the right side of a comparison is always the string "active", even if the data has a field called active. This only applies to comparisons — outside of comparisons, "active" would resolve to the field value.

Logical operators

Operator	Description	Example	Result
`&&`	Logical AND	`{{age >= 18 && status == "active"}}`	`true` if both are true
`\|\|`	Logical OR	`{{role == "admin" \|\| role == "owner"}}`	`true` if either is true

Short-circuit evaluation

Logical operators use short-circuit evaluation:

&& — if the left side is falsy, the right side is not evaluated
|| — if the left side is truthy, the right side is not evaluated

Operator precedence

From highest to lowest:

** (exponentiation)
*, /, % (multiplicative)
+, - (additive)
>, <, >=, <= (relational)
==, ===, !=, !== (equality)
&& (logical AND)
|| (logical OR)

Use parentheses to override precedence:


{{(price + tax) * quantity}}     → adds first, then multiplies
{{price + tax * quantity}}       → multiplies first, then adds