Jinjava tags
Tags are jinjava-based functions. They enable easier access to some jinjava expressions, with additional or alternative logic tailored to the needs of our clients.
You can find the snippets in our Github repository: https://github.com/Synerise/jinja-code-snippet
Tag delimiters
They can use two types of delimiters:
{% %}- available in all tags.{%- -%}- available in tags that have an opening and closing statement. Unnecessary whitespace inside the tags is removed. Using these delimiters where possible is recommended for improved performance.
Example:
Input:
{% set b = 'I remove the whitespace' %}
{%- if b -%}
{{b}}
End of IF
{%- endif -%}Data sent to the browser:
"I remove the whitespace\nEnd of IF"Append
You can use do append to add an item to a list.
Syntax:
{% do listname.append('string')}Example:
This example uses do.append and loop.index to iterate over a list of items and pull corresponding values from another list to create an array of objects with values from both lists.
<!-- List of items: -->
{% set itemsArray = ['item1','item2','item3'] %}
<!-- List of prices for the items: -->
{% set pricesArray = ['item1_price','item2_price','item3_price'] %}
<!-- Empty array to fill with objects: -->
{% set arrayWithItemsAndPrices = [] %}
<!-- Start iterating over itemsArray -->
{%- for item in itemsArray -%}
<!-- Set variable to store index of the current iteration: -->
{% set index=loop.index0 %}
<!-- Append object to the array -->
{% do arrayWithItemsAndPrices.append({
item: item,
price: pricesArray[index],
index: index
})
%}
{%- endfor -%}In the object:
itemis the current item fromitemsArray,priceis pulled from the corresponding index frompricesArray,indexis the current iteration
Result:
The arrayWithItemsAndPrices array is the following:
[
{item=item1, price=item1_price, index=0},
{item=item2, price=item2_price, index=1},
{item=item3, price=item3_price, index=2}
]AutoEscape
Autoescape the tag’s contents.
{%- autoescape -%}
<!--Code to escape-->
{%- endautoescape -%}Call
In some cases, it can be useful to pass a macro to another macro. For this purpose, you can use the special call block.
This is a simple dialog rendered by using a macro and a call block:
{%- macro render_dialog(title, class='dialog') -%}
<div class="{{ class }}">
<h2>{{ title }}</h2>
<div class="contents">
{{ caller() }}
</div>
</div>
{%- endmacro -%}
{%- call render_dialog('Hello World') -%}
This is a simple dialog rendered by using a macro and
a call block.
{%- endcall -%}It’s also possible to pass arguments back to the call block. This makes it useful as a replacement for loops. Generally speaking, a call block works exactly like a macro, but it doesn’t have a name. Here’s an example of how a call block can be used with arguments:
{%- macro dump_users(users) -%}
<ul>
{%- for user in users -%}
<li>
<p>{{ user.username|e }}</p>
{{ caller(user) }}
</li>
{%- endfor -%}
</ul>
{%- endmacro -%}
{%- call(user) dump_users(list_of_user) -%}
<dl>
<dl>Realname</dl>
<dd>{{ user.realname|e }}</dd>
<dl>Description</dl>
<dd>{{ user.description }}</dd>
</dl>
{%- endcall -%}Cycle
The cycle tag can be used within a for loop to cycle through a series of string values and print them with each iteration.
Parameters:
| Type | Required | Description |
|---|---|---|
| list | yes | A comma-separated list of strings to print with each iteration. The list will repeat if there are more iterations than string parameter values. |
In the example below, the classes odd and even are applied to posts in a listing:
{%- for content in contents -%}
<div class="post-item {% cycle 'odd','even' %}">
Blog post content
</div>
{%- endfor -%}If, else if, else
Outputs inner content if expression evaluates to true, otherwise evaluates elif blocks, finally outputting the content of the else block present (if no elif block evaluated to true).
{%- if number <= 2 -%}
Variable named number is less than or equal to 2.
{%- elif number <= 4 -%}
Variable named number is less than or equal to 4.
{%- elif number <= 6 -%}
Variable named number is less than or equal to 6.
{%- else -%}
Variable named number is greater than 6.
{%- endif -%}Combining conditions
You can combine conditions with the following operators:
and/&&or/||not
If a condition uses functions and includes spaces (such as in tests), it may be evaluated incorrectly or stop the rendering. For best results, we recommend using brackets with all conditions.
Examples:
{%- if (2 == 2) and (3 == 3) -%} // recommended
{%- if (5 is divisibleby 5) and (2 == 2) -%} // correct, recommended
{% if (not(5 is divisibleby 4)) and (2 == 2) %} // correct, recommended
{%- if 5 is divisibleby 5 and 2 == 2 -%} // INCORRECT
{%- if 2 == 2 and 3 == 3 -%} // NOT recommendedFor
Outputs the inner content for each item in the given iterable.
Examples:
Iterating over a list.
{% set names = ["John", "Kate", "Bob"] %}
{%- for item in names -%}
Hello, {{ item }}!
{%- endfor -%}Loop variables
Inside the for loop, you can access special variables.
| col1 | col2 |
|---|---|
loop.index |
The current iteration, first iteration is 1 |
loop.index0 |
The current iteration, first iteration is 0 |
loop.revindex |
Iterations until end of loop, last iteration is 1 |
loop.revindex0 |
Iterations until end of loop, last iteration is 0 |
loop.first |
true if this is the first iteration |
loop.last |
true if this is the last iteration |
loop.length |
Total number of items in the loop |
loop.cycle() |
Helper function for cycling, see example below the table |
loop.depth |
The depth of the current iteration in a recursive loop, starting at 1 |
loop.depth0 |
The depth of the current iteration in a recursive loop, starting at 0 |
Example
Input:
{% set array = ["q","w","e","r","t"] %}
{%- for item in array -%}
Item: {{ item }}
Index: {{ loop.index }}
Revindex: {{ loop.revindex }}
Cycle: {{ loop.cycle('foo','bar','baz') }}
{%- endfor -%}Output:
Item: q
Index: 1
Revindex: 5
Cycle: foo
Item: w
Index: 2
Revindex: 4
Cycle: bar
Item: e
Index: 3
Revindex: 3
Cycle: baz
Item: r
Index: 4
Revindex: 2
Cycle: foo
Item: t
Index: 5
Revindex: 1
Cycle: barGet
See “Object properties” in “Insert usage”.
Ifchanged
Outputs the tag contents if the given variable has changed since a prior invocation of this tag.
{%- ifchanged variable -%}
<!-- Code to execute if the variable has changed -->
{%- endifchanged -%}Macro
Macros allow you to print multiple statements with a dynamic value or values.
Basic macro syntax:
<!-- Defining the macro -->
{%- macro name_of_macro(argument_name, argument_name2) -%}
{{ argument_name }}
{{ argument_name2 }}
{%- endmacro -%}
<!-- Calling the macro -->
{{ name_of_macro("value to pass to argument 1", "value to pass to argument 2") }}Example of a macro used to print CSS3 properties with the various vendor prefixes.
{%- macro trans(value) -%}
-webkit-transition: {{value}};
-moz-transition: {{value}};
-o-transition: {{value}};
-ms-transition: {{value}};
transition: {{value}};
{%- endmacro -%}The macro can then be called like a function. The macro is printed for anchor tags in CSS.
a { {{ trans("all .2s ease-in-out") }} }Echoes the result of the expression.
Examples:
{% set string_to_echo = "Print me" %}
{% print string_to_echo %}{% print -65|abs %}Range
Generates an array of integers. The array can’t be longer than 1000 items.
range(start,stop,step)| Parameter | Required | Default | Description |
|---|---|---|---|
| start | no | 0 |
The first value in the array. |
| stop | yes | n/a | The limit at which the array ends. The value of the limit is excluded from the array. |
| step | no | 1 |
The increment between items. Can be negative. |
Examples:
Default start and step:
{% set foo=range(5) %}
{{ foo }}
OUTPUT:
[0, 1, 2, 3, 4]Start defined, step default:
{% set foo=range(2,10) %}
{{foo}}
OUTPUT:
[2, 3, 4, 5, 6, 7, 8, 9]Defined start and step. The value of stop isn’t included in the array.
{% set foo=range(2,10,2) %}
{{foo}}
OUTPUT:
[2, 4, 6, 8]Negative increment. The value of stop isn’t included in the array. In this case, start must be higher than stop!
{% set foo=range(10,2,-2) %}
{{foo}}
OUTPUT:
[10, 8, 6, 4]Raw
Processes all inner expressions as plain text.
{%- raw -%}
The personalization token for a contact's first name is {{ contact.firstname }}
{%- endraw -%}Set
Assigns the value or result of a statement to a variable.
Basic syntax:
{% set variableName = variableValue %}The value can be a string, a number, a boolean, or a sequence.
Example:
Set a variable and print the variable in an expression:
{% set primaryColor = "#F7761F" %}
{{ primaryColor }}You can combine multiple values or variables into a sequence variable.
{% set var_one = "String 1" %}
{% set var_two = "String 2" %}
{% set sequence = [var_one, var_two] %}Try/catch
The try/catch syntax can be used to create a fallback mechanism for Jinjava that is syntactically correct, but can’t be processed, such as referencing an attribute that doesn’t exist.
You can only include one catch statement, but you can nest another try/catch blocks inside it (see examples below).
In this example, the Jinjava in the try/catch block is correct, but references a variable that doesn’t exist. The code from the catch statement is executed.
{% try %}
{{ thisVariableDoesntExist }}
{% catch %}
I didn't find the variable!
{% endtry %}OUTPUT:
I didn't find the variable!
The following table explains the behavior of the block in some common scenarios.
| Scenario | Result |
|---|---|
| Variable doesn’t exist | catch |
Syntax error in try or catch statement |
Rendering fails |
| Profile attribute with no value in the context profile | catch |
| Profile attribute doesn’t exist at all in the database | catch |
| Aggregate that doesn’t exist or returns no value | catch |
| Expression doesn’t exist | catch |
Expression exists, returns null |
try |
Mathematical operation (other than +) on a null result from an expression.Null is treated as a string. + results in concatenation. |
Rendering fails |
| Metric doesn’t exist | catch |
| Metric exists, but required item context isn’t provided | catch |
| Catalog/column/item doesn’t exist | catch |
Catalog/column/item doesn’t exist, but allowEmpty=True |
try |
| Recommendation doesn’t exist | catch |
| Recommendation returns an error | catch |
| Recommendation in draft status | catch |
| Required context missing in recommendation | catch |
| Recommendation context references item that doesn’t exist | catch |
| Voucher pool doesn’t exist or expired | catch |
| No available vouchers in pool | catch |
{% kill %} function in try statement |
Rendering fails1 |
| Reference to a function that doesn’t exist | Rendering fails |
try statement is empty |
try (returns empty string) |
try statement fails, but catch doesn’t exist/is empty |
Empty string |
catch references a variable set in try |
Rendering fails (variable is local to try, catch is sibling) |
try references a variable set in an ancestor |
try (variables are inherited) |
Error in catch statement |
Rendering fails |
| Type error, such as a mathematical operation on a string | Rendering fails |
| Illegal characters in variable names | Rendering fails |
1 In certain situations, such as placing the kill function inside another function, the kill function is processed as normal and the catch statement is rendered.
Unless
Unless is a conditional just like ‘if’, but works on an inverse logic.
{%- unless x < 0 -%}
x is greater than zero
{%- endunless -%}Update
Creates or updates the properties of an object.
Example:
{% set product = {'category':'sneakers'} %}
Initial object: {{product}}
<br>
{% set colorData = {'color':'red','size': 8} %}
{% do product.update(colorData) %}
Added color and size: {{product}}
<br>
{% set newColorData = {'color':'blue'} %}
{% do product.update(newColorData) %}
Updated color: {{product}}Output:
Initial object: {category=sneakers}
<br>
Added color and size: {category=sneakers, color=red, size=8}
<br>
Updated color: {category=sneakers, color=blue, size=8}
