Discussion: What patterns should be allowed for attributes and properties.

[theengineear]

Attributes

// accepted
html`<div foo="${bar}"></div>`
html`<div fOo="${bar}"></div>`
html`<div f-o-o="${bar}"></div>`
html`<div foo-="${bar}"></div>`
html`<div f00="${bar}"></div>`

// rejected
html`<div 1foo="${bar}"></div>`
html`<div f_o_o="${bar}"></div>`
html`<div Foo="${bar}"></div>`
html`<div -foo="${bar}"></div>`
html`<div _foo="${bar}"></div>`

Properties

// accepted
html`<div .foo="${bar}"></div>`
html`<div .fOo="${bar}"></div>`
html`<div .f_o_o="${bar}"></div>`
html`<div .foo_="${bar}"></div>`
html`<div .f00="${bar}"></div>`

// rejected
html`<div .1foo="${bar}"></div>`
html`<div .f-o-o="${bar}"></div>`
html`<div .Foo="${bar}"></div>`
html`<div .-foo="${bar}"></div>`
html`<div ._foo="${bar}"></div>`

Context

I recently went to port some code that was using a property like _internal, and that cannot be bound via ._internal="${whatever}". At first, I thought it would be better to allow it… but then I thought… it’s really not internal, it’s on the public interface. I am waffling a bit on how restrictive / flexible to be here.