if ViewHelper <f:if>¶
This ViewHelper implements an if/else condition.
Fluid Boolean Rules / Conditions:¶
A condition is evaluated as a boolean value, so you can use any
boolean argument, like a variable.
Alternatively, you can use a full boolean expression.
The entered expression is evaluated as a PHP expression. You can
combine multiple expressions via && (logical AND) and
|| (logical OR).
An expression can also be prepended with the ! ("not") character,
which will negate that expression.
Have a look into the Fluid section of the "TYPO3 Explained" Documentation for more details about complex conditions.
Boolean expressions have the following form:
is true variant: {variable}:
<f:if condition="{foo}">
Will be shown if foo is truthy.
</f:if>
or is false variant: !{variable}:
<f:if condition="!{foo}">
Will be shown if foo is falsy.
</f:if>
or comparisons with expressions:
XX Comparator YY
Comparator is one of: ==, !=, <, <=, >, >= and %
The % operator (modulo) converts the result of the operation to
boolean.
XX and YY can be one of:
- Number
- String
- Object Accessor (
object.property) - Array
- a ViewHelper
<f:if condition="{rank} > 100">
Will be shown if rank is > 100
</f:if>
<f:if condition="{rank} % 2">
Will be shown if rank % 2 != 0.
</f:if>
<f:if condition="{rank} == {k:bar()}">
Checks if rank is equal to the result of the ViewHelper "k:bar"
</f:if>
<f:if condition="{object.property} == 'stringToCompare'">
Will result in true if {object.property}'s represented value
equals 'stringToCompare'.
</f:if>
Examples¶
Basic usage¶
<f:if condition="somecondition">
This is being shown in case the condition matches
</f:if>
Output:
Everything inside the <f:if> tag is being displayed if the condition evaluates to TRUE.
If / then / else¶
<f:if condition="somecondition">
<f:then>
This is being shown in case the condition matches.
</f:then>
<f:else>
This is being displayed in case the condition evaluates to FALSE.
</f:else>
</f:if>
Output:
Everything inside the "then" tag is displayed if the condition evaluates to TRUE.
Otherwise, everything inside the "else" tag is displayed.
Inline notation¶
{f:if(condition: someCondition, then: 'condition is met', else: 'condition is not met')}
Output:
The value of the "then" attribute is displayed if the condition evaluates to TRUE.
Otherwise, everything the value of the "else" attribute is displayed.
Combining multiple conditions¶
<f:if condition="{user.rank} > 100 && {user.type} == 'contributor'">
<f:then>
This is being shown in case both conditions match.
</f:then>
<f:else if="{user.rank} > 200 && ({user.type} == 'contributor' || {user.type} == 'developer')">
This is being displayed in case the first block of the condition evaluates to TRUE and any condition in
the second condition block evaluates to TRUE.
</f:else>
<f:else>
This is being displayed when none of the above conditions evaluated to TRUE.
</f:else>
</f:if>
Output:
Depending on which expression evaluated to TRUE, that value is displayed.
If no expression matched, the contents inside the final "else" tag are displayed.
Arguments¶
then¶
- DataType
- mixed
- Required
- false
- Description
- Value to be returned if the condition if met.
else¶
- DataType
- mixed
- Required
- false
- Description
- Value to be returned if the condition if not met.
condition¶
- DataType
- boolean
- Required
- false
- Description
- Condition expression conforming to Fluid boolean rules