1 files changed, 77 insertions, 0 deletions
diff --git a/alpinejs/packages/alpinejs/src/interceptor.js b/alpinejs/packages/alpinejs/src/interceptor.js
new file mode 100644
index 0000000..0f9f557
--- /dev/null
+++ b/alpinejs/packages/alpinejs/src/interceptor.js
@@ -0,0 +1,77 @@
+// Warning: The concept of "interceptors" in Alpine is not public API and is subject to change
+// without tagging a major release.
+
+export function initInterceptors(data) {
+    let isObject = val => typeof val === 'object' && !Array.isArray(val) && val !== null
+
+    let recurse = (obj, basePath = '') => {
+        Object.entries(Object.getOwnPropertyDescriptors(obj)).forEach(([key, { value, enumerable }]) => {
+            // Skip getters.
+            if (enumerable === false || value === undefined) return
+
+            let path = basePath === '' ? key : `${basePath}.${key}`
+
+            if (typeof value === 'object' && value !== null && value._x_interceptor) {
+                obj[key] = value.initialize(data, path, key)
+            } else {
+                if (isObject(value) && value !== obj && ! (value instanceof Element)) {
+                    recurse(value, path)
+                }
+            }
+        })
+    }
+
+    return recurse(data)
+}
+
+export function interceptor(callback, mutateObj = () => {}) {
+    let obj = {
+        initialValue: undefined,
+
+        _x_interceptor: true,
+
+        initialize(data, path, key) {
+            return callback(this.initialValue, () => get(data, path), (value) => set(data, path, value), path, key)
+        }
+    }
+
+    mutateObj(obj)
+
+    return initialValue => {
+        if (typeof initialValue === 'object' && initialValue !== null && initialValue._x_interceptor) {
+            // Support nesting interceptors.
+            let initialize = obj.initialize.bind(obj)
+
+            obj.initialize = (data, path, key) => {
+                let innerValue = initialValue.initialize(data, path, key)
+
+                obj.initialValue = innerValue
+
+                return initialize(data, path, key)
+            }
+        } else {
+            obj.initialValue = initialValue
+        }
+
+        return obj
+    }
+}
+
+function get(obj, path) {
+    return path.split('.').reduce((carry, segment) => carry[segment], obj)
+}
+
+function set(obj, path, value) {
+    if (typeof path === 'string') path = path.split('.')
+
+    if (path.length === 1) obj[path[0]] = value;
+       else if (path.length === 0) throw error;
+    else {
+       if (obj[path[0]])
+          return set(obj[path[0]], path.slice(1), value);
+       else {
+          obj[path[0]] = {};
+          return set(obj[path[0]], path.slice(1), value);
+       }
+    }
+}