Escape Special XML Characters in Default Values

The default attribute of a property type lets you set a value for the property before an end user has a chance to change the input. Setting the default value of a custom property type from the js-meta.xml file requires you to escape any special characters in that value.

It's standard practice in XML documents to ensure that special characters in a value don't affect the validity of the whole XML document. (This consideration generally doesn't apply to primitive types.) For properties that directly or indirectly reference a custom property type that's defined in its schema as lightning__objectType, lightning__dateTimeType, or lightning__richTextType, you may need to escape special characters in those values.

For example, if a component has a property tag that uses lightning__richTextType, this is how to specify any HTML or XML usage in the default attribute that you'd have to escape, such as "<strong>bold text</strong>."

Similarly, if a component has a property type reference that uses the lightning__objectType, this is how to specify a default object value such as "{"state":"California", "city":"San Francisco"}".