Update API.md

API.md

@@ -1,10 +1,34 @@
+## Introduction
 
 The `Topo` object is the container for topologically sorting a list of nodes with non-circular interdependencies.
 
+## Example
+
+```js
+const Topo = require('@hapi/topo');
+
+const morning = new Topo();
+
+morning.add('Nap', { after: ['breakfast', 'prep'] });
+
+morning.add([
+    'Make toast',
+    'Pour juice'
+], { before: 'breakfast', group: 'prep' });
+
+morning.add('Eat breakfast', { group: 'breakfast' });
+
+morning.nodes;        // ['Make toast', 'Pour juice', 'Eat breakfast', 'Nap']
+```
+
+## Methods
+
 ### `new Topo()`
+
 Creates a new `Topo` object.
 
 ### `topo.add(nodes, [options])`
+
 Specifies an additional node or list of nodes to be topologically sorted where:
   - `nodes` - a mixed value or array of mixed values to be added as nodes to the topologically sorted list.
   - `options` - optional sorting information about the `nodes`:
@@ -16,9 +40,11 @@ Specifies an additional node or list of nodes to be topologically sorted where:
 Returns an array of the topologically sorted nodes.
 
 ### `topo.nodes`
+
 An array of the topologically sorted nodes.  This list is renewed upon each call to [`topo.add()`](#topoaddnodes-options).
 
 ### `topo.merge(others)`
+
 Merges another `Topo` object into the current object where:
 - `others` - the other object or array of objects to be merged into the current one. `null`
   values are ignored.
@@ -27,4 +53,4 @@ Returns an array of the topologically sorted nodes. Will throw if a dependency e
 combined items.
 
 If the order in which items have been added to each list matters, use the `sort` option in `topo.add()` with an incrementing
-value providing an absolute sort order among all items added to either object.
+value providing an absolute sort order among all items added to either object.