chore: add documentation for ordering

Author: Olivier Costi

README.md

@@ -412,6 +412,81 @@ wServices['article'].some({
 
 This only returns the articleNumber property of all articles.
 
+#### Ordering
+
+With the some function you can order requested data. You can either merely order by fields or by complex expressions.
+
+```ts
+/**
+ * Order by articleNumber in ascending order.
+ *
+ * ?orderBy=articleNumber
+ */
+wServices['article'].some({
+  orderBy: [{ FIELD: 'createdDate', SORT: 'asc' }]
+});
+```
+
+```ts
+/**
+ * First order by createdDate in ascending order, then by articleNumber in descending order
+ * If you omit SORT the default ordering will be set to ascending.
+ *
+ * ?orderBy=createdDate asc, articleNumber desc
+ */
+wServices['article'].some({
+  orderBy: [{ FIELD: 'createdDate' }, { FIELD: 'articleNumber', SORT: 'desc' }]
+});
+```
+
+```ts
+/**
+ * First order by internalNote in ascending order, if it is not null,
+ * then by packagingQuantity, if is greater than 400. At last,
+ * order by articleNumber in ascending order
+ *
+ * ?orderBy=(not internalNote null) ? 1 : ((packagingQuantity.price > 400) ? 2 : 3) asc, articleNumber asc
+ *
+ */
+wServices['article'].some({
+  orderBy: [
+    {
+      CASE: [
+        'WHEN',
+        { internalNote: { NULL: false } },
+        'THEN',
+        1,
+        'ELSE',
+        { CASE: ['WHEN', { packagingQuantity: { GT: 400 } }, 'THEN', 2, 'ELSE', 3] }
+      ],
+      SORT: 'asc'
+    },
+    { FIELD: 'articleNumber' }
+  ]
+});
+```
+
+There are three modifier functions, `TRIM`, `LOWER` and `LENGTH`, which can be used to adjust the expessions:
+
+```ts
+/**
+ * First order by the length of the trimmed lastName in descending order, then by firstName in ascending order
+ *
+ * ?orderBy=length(trim(lastName)) desc, firstName asc
+ */
+wServices['party'].some({
+  orderBy: [
+    {
+      FIELD: 'lastName',
+      LENGTH: true,
+      TRIM: true,
+      SORT: 'desc'
+    },
+    { FIELD: 'firstName' }
+  ]
+});
+```
+
 ### Aborting a request
 
 To abort a request an AbortController has to be instantiated and its signal has to be passed to the request. The controller can