mojo/public/tools/bindings/generators/js_templates/enum_definition.tmpl

{%- macro enum_def(enum_name, enum) -%}
  {{enum_name}} = {};
{%-   set prev_enum = 0 %}
{%-   for field in enum.fields %}
{%-     if field.value %}
  {{enum_name}}.{{field.name}} = {{field.value|expression_to_text}};
{%-     elif loop.first %}
  {{enum_name}}.{{field.name}} = 0;
{%-     else %}
  {{enum_name}}.{{field.name}} = {{enum_name}}.{{enum.fields[loop.index0 - 1].name}} + 1;
{%-     endif %}
{%-   endfor %}

  {{enum_name}}.isKnownEnumValue = function(value) {
{%-   if enum.fields %}
    switch (value) {
{%-       for enum_field in enum.fields|groupby('numeric_value') %}
    case {{enum_field[0]}}:
{%-     endfor %}
      return true;
    }
{%-   endif %}
    return false;
  };

  {{enum_name}}.validate = function(enumValue) {
    var isExtensible = {% if enum.extensible %}true{% else %}false{% endif %};
    if (isExtensible || this.isKnownEnumValue(enumValue))
      return validator.validationError.NONE;

    return validator.validationError.UNKNOWN_ENUM_VALUE;
  };
{%- endmacro %}