Add .Options.JSON to custom API

docs/custom-api.md

@@ -415,6 +415,14 @@ The following functions are available on the `JSON` object:
 - `Array(key string) []JSON`: Returns the value of the key as an array of `JSON` objects.
 - `Exists(key string) bool`: Returns true if the key exists in the JSON object.
 
+The following functions are available on the `Options` object:
+
+- `StringOr(key string, default string) string`: Returns the value of the key as a string, or the default value if the key does not exist.
+- `IntOr(key string, default int) int`: Returns the value of the key as an integer, or the default value if the key does not exist.
+- `FloatOr(key string, default float) float`: Returns the value of the key as a float, or the default value if the key does not exist.
+- `BoolOr(key string, default bool) bool`: Returns the value of the key as a boolean, or the default value if the key does not exist.
+- `JSON(key string) JSON`: Returns the value of the key as a stringified `JSON` object, or throws an error if the key does not exist.
+
 The following helper functions provided by Glance are available:
 
 - `toFloat(i int) float`: Converts an integer to a float.

internal/glance/widget-custom-api.go

@@ -108,6 +108,20 @@ func (o *customAPIOptions) BoolOr(key string, defaultValue bool) bool {
 	return customAPIGetOptionOrDefault(*o, key, defaultValue)
 }
 
+func (o *customAPIOptions) JSON(key string) string {
+	value, exists := (*o)[key]
+	if !exists {
+		panic(fmt.Sprintf("key %q does not exist in options", key))
+	}
+
+	encoded, err := json.Marshal(value)
+	if err != nil {
+		panic(fmt.Sprintf("marshaling %s: %v", key, err))
+	}
+
+	return string(encoded)
+}
+
 func customAPIGetOptionOrDefault[T any](o customAPIOptions, key string, defaultValue T) T {
 	if value, exists := o[key]; exists {
 		if typedValue, ok := value.(T); ok {