required bug / string|undefined -> boolean

[mrinc]

Ref: https://github.com/nicojs/typed-html/blob/88a6a6219bbf4d9368537ee29419d29671573093/src/jsx/element-types.d.ts#L150

As this is a string|undefined, it denotes required or not defined as per html spec... but...
If you pass in undefined the following error occurs:

https://github.com/nicojs/typed-html/blob/88a6a6219bbf4d9368537ee29419d29671573093/src/elements.tsx#L66

TypeError: Cannot read properties of undefined (reading 'toString')

2 step recommendation:

https://github.com/nicojs/typed-html/blob/88a6a6219bbf4d9368537ee29419d29671573093/src/jsx/element-types.d.ts#L150
From: required?: string;
To: required?: boolean;

• AND

https://github.com/nicojs/typed-html/blob/88a6a6219bbf4d9368537ee29419d29671573093/src/elements.tsx#L66
From:

return makeAttribute(escapeAttrNodeValue(value.toString()));

To:

return makeAttribute(value !== undefined && value !== null && typeof value.toString === 'function' ? escapeAttrNodeValue(value.toString()) : '');

• OR

  const attributeToString = (attributes: Attributes) => (name: string): string => {
  const value = attributes[name];
  const formattedName = toKebabCase(name);
  const makeAttribute = (value: string) => `${formattedName}="${value}"`;
  if (typeof value === 'undefined') {
      return '';
  }
  if (value instanceof Date) {
      return makeAttribute(value.toISOString());
  } else switch (typeof value) {
      case 'boolean':
          // https://www.w3.org/TR/2008/WD-html5-20080610/semantics.html#boolean
          if (value) {
              return formattedName;
          } else {
              return '';
          }
      default:
          return makeAttribute(escapeAttrNodeValue(value.toString()));
  }
  };

Happy to push a PR for this, let me know.