no-legacy-template-syntax.md

Detects usages of legacy binding syntax (no-legacy-template-syntax)

Legacy lit-extended syntax is no longer supported so any uses of it are likely to be mistakes.

Rule Details

This rule disallows use of legacy lit-extended syntax in templates.

The following patterns are considered warnings:

html`<x-foo bar?=${x}>`; // boolean
html`<x-foo on-bar=${x}>`; // event listener
html`<x-foo bar$=${x}>`; // attribute

The following patterns are not warnings:

html`<x-foo ?bar=${x}>`; // boolean
html`<x-foo @bar=${x}>`; // event listener
html`<x-foo bar=${x}>`; // attribute (Previously, property)
html`<x-foo .bar=${x}>`; // property

When Not To Use It

If you use lit-extended syntax, then you will not need this rule.