2.2 KiB
Default Functions
Sprig provides tools for setting default values for templates.
default
To set a simple default value, use default:
default "foo" .Bar
In the above, if .Bar evaluates to a non-empty value, it will be used. But if
it is empty, foo will be returned instead.
The definition of "empty" depends on type:
- Numeric: 0
- String: ""
- Lists:
[] - Dicts:
{} - Boolean:
false - And always
nil(aka null)
For structs, there is no definition of empty, so a struct will never return the default.
empty
The empty function returns true if the given value is considered empty, and
false otherwise. The empty values are listed in the default section.
empty .Foo
Note that in Go template conditionals, emptiness is calculated for you. Thus,
you rarely need if empty .Foo. Instead, just use if .Foo.
coalesce
The coalesce function takes a list of values and returns the first non-empty
one.
coalesce 0 1 2
The above returns 1.
This function is useful for scanning through multiple variables or values:
coalesce .name .parent.name "Matt"
The above will first check to see if .name is empty. If it is not, it will return
that value. If it is empty, coalesce will evaluate .parent.name for emptiness.
Finally, if both .name and .parent.name are empty, it will return Matt.
toJson
The toJson function encodes an item into a JSON string.
toJson .Item
The above returns JSON string representation of .Item.
toPrettyJson
The toPrettyJson function encodes an item into a pretty (indented) JSON string.
toPrettyJson .Item
The above returns indented JSON string representation of .Item.
ternary
The ternary function takes two values, and a test value. If the test value is
true, the first value will be returned. If the test value is empty, the second
value will be returned. This is similar to the c ternary operator.
true test value
ternary "foo" "bar" true
or
true | ternary "foo" "bar"
The above returns "foo".
false test value
ternary "foo" "bar" false
or
false | ternary "foo" "bar"
The above returns "bar".