feat: add template-require-input-type

[johanrd]

Note

This is part of a series where Claude has audited eslint-plugin-ember against jsx-a11y, vuejs-accessibility, angular-eslint, lit-a11y and html-validate, ember-template-lint, and the HTML and WCAG specs.

See html-validate no-implicit-input-type for the peer rule concept.

Adds template-require-input-type: rejects <input type="..."> values outside the 22 HTML-defined input types (always on, fixable). Provides an opt-in requireExplicit: true mode that additionally flags <input> without a type attribute.

Complements the existing template-require-button-type rule.

Premises

Premise 1 — correctness (always-on check): HTML spec §4.10.5 defines 22 input type states. The spec states: "The attribute's missing value default and invalid value default are both the Text state." So <input type="foo"> silently falls back to text without any error — a genuine silent-failure class where the author wrote a value that looks meaningful (or miskeyed a valid one, e.g. tex) and the browser quietly does something else.

Premise 2 — style/consistency (opt-in check): <input> with no type attribute is 100% spec-compliant. Requiring an explicit type is an authoring-consistency choice analogous to template-require-button-type. The opt-in is off by default because the correctness argument for inputs is thinner than for <button> (no accidental-submit footgun when type is missing).

Flags (default: invalid values only)

<input type='' />
<input type='foo' />
<input type='TEXTY' />

Flags (with requireExplicit: true)

Adds missing-type to the above:

<input />
<input name='email' />

Allows

<input type='text' />
<input type='email' />
<input type='datetime-local' />
<input type={{this.inputType}} />    {{! dynamic — skipped }}
<input />                            {{! allowed with default config (requireExplicit: false) }}

Prior art

Plugin	Equivalent	Notes
html-validate	no-implicit-input-type	Reports <input> missing a type. Does NOT validate the value (this rule adds that).
@angular-eslint/template	button-has-type	Same design for <button>, not <input>.
jsx-a11y	—	No equivalent.
vuejs-accessibility	—	No equivalent.
lit-a11y	—	No equivalent.

Opt-in: not added to any preset config. Fixable with --fix to type="text" (the HTML default).