Add iif (immediate if) template function/filter (#61428)

.pre-commit-config.yaml

@@ -17,7 +17,7 @@ repos:
     hooks:
       - id: codespell
         args:
-          - --ignore-words-list=hass,alot,datas,dof,dur,ether,farenheit,hist,iff,ines,ist,lightsensor,mut,nd,pres,referer,rime,ser,serie,te,technik,ue,uint,visability,wan,wanna,withing,iam,incomfort,ba,haa
+          - --ignore-words-list=hass,alot,datas,dof,dur,ether,farenheit,hist,iff,iif,ines,ist,lightsensor,mut,nd,pres,referer,rime,ser,serie,te,technik,ue,uint,visability,wan,wanna,withing,iam,incomfort,ba,haa
           - --skip="./.*,*.csv,*.json"
           - --quiet-level=2
         exclude_types: [csv, json]

homeassistant/helpers/template.py

@@ -1763,6 +1763,25 @@ def slugify(value, separator="_"):
     return slugify_util(value, separator=separator)
 
 
+def iif(
+    value: Any, if_true: Any = True, if_false: Any = False, if_none: Any = _SENTINEL
+) -> Any:
+    """Immediate if function/filter that allow for common if/else constructs.
+
+    https://en.wikipedia.org/wiki/IIf
+
+    Examples:
+        {{ is_state("device_tracker.frenck", "home") | iif("yes", "no") }}
+        {{ iif(1==2, "yes", "no") }}
+        {{ (1 == 1) | iif("yes", "no") }}
+    """
+    if value is None and if_none is not _SENTINEL:
+        return if_none
+    if bool(value):
+        return if_true
+    return if_false
+
+
 @contextmanager
 def set_template(template_str: str, action: str) -> Generator:
     """Store template being parsed or rendered in a Contextvar to aid error handling."""
@@ -1877,6 +1896,7 @@ class TemplateEnvironment(ImmutableSandboxedEnvironment):
         self.filters["int"] = forgiving_int_filter
         self.filters["relative_time"] = relative_time
         self.filters["slugify"] = slugify
+        self.filters["iif"] = iif
         self.globals["log"] = logarithm
         self.globals["sin"] = sine
         self.globals["cos"] = cosine
@@ -1906,6 +1926,7 @@ class TemplateEnvironment(ImmutableSandboxedEnvironment):
         self.globals["pack"] = struct_pack
         self.globals["unpack"] = struct_unpack
         self.globals["slugify"] = slugify
+        self.globals["iif"] = iif
         self.tests["match"] = regex_match
         self.tests["search"] = regex_search
 

tests/helpers/test_template.py

@@ -21,6 +21,7 @@ from homeassistant.const import (
     TEMP_CELSIUS,
     VOLUME_LITERS,
 )
+from homeassistant.core import HomeAssistant
 from homeassistant.exceptions import TemplateError
 from homeassistant.helpers import device_registry as dr, entity, template
 from homeassistant.helpers.entity_platform import EntityPlatform
@@ -3101,6 +3102,38 @@ def test_urlencode(hass):
     assert tpl.async_render() == "the%20quick%20brown%20fox%20%3D%20true"
 
 
+def test_iif(hass: HomeAssistant) -> None:
+    """Test the immediate if function/filter."""
+    tpl = template.Template("{{ (1 == 1) | iif }}", hass)
+    assert tpl.async_render() is True
+
+    tpl = template.Template("{{ (1 == 2) | iif }}", hass)
+    assert tpl.async_render() is False
+
+    tpl = template.Template("{{ (1 == 1) | iif('yes') }}", hass)
+    assert tpl.async_render() == "yes"
+
+    tpl = template.Template("{{ (1 == 2) | iif('yes') }}", hass)
+    assert tpl.async_render() is False
+
+    tpl = template.Template("{{ (1 == 2) | iif('yes', 'no') }}", hass)
+    assert tpl.async_render() == "no"
+
+    tpl = template.Template("{{ not_exists | default(None) | iif('yes', 'no') }}", hass)
+    assert tpl.async_render() == "no"
+
+    tpl = template.Template(
+        "{{ not_exists | default(None) | iif('yes', 'no', 'unknown') }}", hass
+    )
+    assert tpl.async_render() == "unknown"
+
+    tpl = template.Template("{{ iif(1 == 1) }}", hass)
+    assert tpl.async_render() is True
+
+    tpl = template.Template("{{ iif(1 == 2, 'yes', 'no') }}", hass)
+    assert tpl.async_render() == "no"
+
+
 async def test_cache_garbage_collection():
     """Test caching a template."""
     template_string = (