1 files changed, 56 insertions, 0 deletions
diff --git a/packages/gitbook-core/src/reducers/summary.js b/packages/gitbook-core/src/reducers/summary.js
new file mode 100644
index 0000000..0179ecc
--- /dev/null
+++ b/packages/gitbook-core/src/reducers/summary.js
@@ -0,0 +1,56 @@
+const { Record, List } = require('immutable');
+const FileState = require('./file');
+
+class SummaryArticle extends Record({
+    title:    '',
+    depth:    0,
+    path:     '',
+    ref:      '',
+    level:    '',
+    articles: List()
+}) {
+    constructor(state) {
+        super({
+            ...state,
+            articles: (new List(state.articles))
+                .map(article => new SummaryArticle(article))
+        });
+    }
+}
+
+class SummaryPart extends Record({
+    title:    '',
+    articles: List()
+}) {
+    constructor(state) {
+        super({
+            ...state,
+            articles: (new List(state.articles))
+                .map(article => new SummaryArticle(article))
+        });
+    }
+}
+
+
+class SummaryState extends Record({
+    file: new FileState(),
+    parts: List()
+}) {
+    constructor(state = {}) {
+        super({
+            ...state,
+            file:  new FileState(state.file),
+            parts: (new List(state.parts))
+                .map(article => new SummaryPart(article))
+        });
+    }
+
+    static create(state) {
+        return state instanceof SummaryState ?
+            state : new SummaryState(state);
+    }
+}
+
+module.exports = (state, action) => {
+    return SummaryState.create(state);
+};