Built-in filters

[rossmacarthur]

There are a number of filter functions which might be common or useful enough to provide by default. Some options:

Examples

General

Type conversion filters could be useful, e.g.

• bool: convert a value to a boolean using "truthy" logic, e.g. empty string, list, and map is false, zero integer and float is false.
• int: convert from boolean and float to int
• list: convert map to a list of lists of length two.

Booleans

These would be useful for if statements

• eq, ne
• gt, gte, lt, lte
• and, or
• not

Numbers

• abs: returns the absolute value of the number
• add <v>, sub <v>
• mul <v>, div <v>
• round: rounds to the given precision

Strings

• len / length / size: return the length of the string
• lower: convert a string to lowercase
• upper: convert a string to uppercase
• title: convert a string to titlecase
• trim / strip: trims whitespace from a string
• ltrim / lstrip, rtrim / rstrip: trims whitespace from a string from the one end
• reverse: reverses the list
• replace <from> <to>: replaces a substring with another
• append <s>: appends the given string
• prepend <s>: prepends the given string

Lists

• len / length / size: return the length of the list
• first: return the first item in a list
• last: return the last item in a list
• slice: slice a list
• nth <n>: return the nth item in a list
• join <sep> / concat <sep>: join a sequence by separator
• uniq: remove any duplicate items from the list
• sorted: sorts the list (? how should differently typed Values be ordered?)

Maps

• len / length / size: return the length of the map
• keys: returns a list of the keys in the map
• values: returns a list of the values in the map
• first: return the first item in the map
• last: return the last item in the map

[qq253498229]

I think json and date are also commonly used.

{{ my_object_instance | json }} => {"field1" : "text1"}
{{ create_time | date: "yyyy-MM-dd HH:mm:ss.SSS" }} => 2024-08-23 10:00:00.000