Complex Template Expressions (Beta)

I like this feature, but only in small doses.

LWC now lets you write JavaScript expressions directly in templates, for example:

<lightning-formatted-number
  value={amount * (1 + taxRate)}
  format-style="currency">
</lightning-formatted-number>

For tiny calculations, this is clean. No extra getter, less file hopping, and faster component authoring.

Where it works well

• Basic math (x + y, percentages, small currency math)
• Simple checks (items.length > 10, null/empty guards)
• Lightweight display-only decisions

Where it starts to hurt

• Nested conditional logic
• Long expressions with multiple operators
• Anything you need to unit test in isolation
• Anything business-critical

At that point, the template stops being declarative and starts feeling like inline logic soup.

My rule of thumb

If I need more than one quick read to understand the expression, it should be a getter.

Templates should explain structure. Getters (or controller logic) should explain behavior.

So yes, this beta is useful, but I would keep it limited to the truly simple cases.