[update] correct data/treecollection api descriptions

Author: mafanya23

docs/data_collection/api/datacollection_add_method.md

@@ -12,10 +12,15 @@ description: You can explore the add method of DataCollection in the documentati
 Please note that data should be loaded into DataCollection via the `parse()` method. The `add()` method is primarily intended for loading standalone elements or small groups of elements, so its loads data slower than the `parse()` method.
 :::
 
-@signature: {'add(new_item: object | object[], index?: number): (string | number) | (string | number)[];'}
+### Usage
+
+~~~jsx
+type Id = string | number; 
+add(newItem: IDataItem | IDataItem[], index?: number): Id | Id[];
+~~~
 
 @params:
-- `new_item: object | array` - the object of a new item or an array of item objects
+- `newItem: IDataItem | IDataItem[]` - the object of a new item or an array of item objects
 - `index?: number` - optional, the index of the position starting from which new items will be added
 
 @returns:

docs/data_collection/api/datacollection_filter_method.md

@@ -12,22 +12,20 @@ description: You can explore the filter method of DataCollection in the document
 
 @params:
 
-<table>
-    <tbody>
-        <tr>
-            <td><b>rule</b></td>
-            <td>(<i>function | object</i>) optional, the filtering criteria. It can be:<ul><li>a filtering function. It takes as a parameter a data item and returns <i>true/false</i></li><li>an object with the following attributes:<ul><li><b>`by?: string | number`</b> - optional, the id of a column</li><li><b>`match?: string`</b> - optional, a pattern to match </li><li><b>`compare?: function`</b> - optional, a function for extended filtering that takes the following parameters:<ul><li><b>value</b> - the value to compare </li><li><b>match</b> - a pattern to match </li><li><b>item</b> - a data item the values of which should be compared</li></ul></li></ul></li></ul></td>
-        </tr>
-        <tr>
-            <td><b>config</b></td>
-            <td>(<i>object</i>) optional, an object with the following properties:<ul><li><b>`id?: string`</b> - optional, the id of the filter</li><li><b>`add?: boolean`</b> - optional, defines whether each next filtering will be applied to the already filtered data (<i>true</i>), or to the initial data (<i>false</i>, default)</li><li><b>`permanent?: boolean`</b> - optional, <i>true</i> to make the current filter permanent. It will be applied even if the next filtering doesn't have the <b>`add:true`</b> property in its configuration object. Such a filter can be removed just with the <a href="../datacollection_resetfilter_method/">`resetFilter()`</a> method</li></ul></td>
-        </tr>
-        <tr>
-            <td><b>silent</b></td>
-            <td>(<i>boolean</i>) optional, if set to <i>true</i>, the method will be called without triggering events, <i>false</i> by default</td>
-        </tr>
-    </tbody>
-</table>
+- `rule?: function | object` - optional, the filtering criteria
+    - If set as a *function*, filtering will be applied by the rule specified in the function. It takes as a parameter a data item and returns *true/false*
+    - If set as an *object*, the parameter has the following attributes:
+        - `by?: string | number` - optional, the id of a data field 
+        - `match?: string` - optional, a pattern to match
+        - `compare?: function` - optional, a function for extended filtering that takes the following parameters:
+            - `value` - the value to compare 
+            - `match` - a pattern to match
+            - `item` - a data item the values of which should be compared 
+- `config?: object` - optional, an object with the following properties:
+    - `id?: string` - optional, the id of the filter
+    - `add?: boolean` - optional, defines whether each next filtering will be applied to the already filtered data (<i>true</i>), or to the initial data (<i>false</i>, default)
+    - `permanent?: boolean` - optional, *true* to make the current filter permanent. It will be applied even if the next filtering doesn't have the `add:true` property in its configuration object. Such a filter can be removed just with the [resetFilter()](data_collection/api/datacollection_resetfilter_method.md) method
+- `silent?: boolean` - optional, if set to <i>true</i>, the method will be called without triggering events, <i>false</i> by default
 
 :::info
 Note that after calling the method with the `silent:true` parameter, you may need to repaint the component with the `paint()` method.

docs/data_collection/api/datacollection_find_method.md

@@ -8,7 +8,7 @@ description: You can explore the find method of DataCollection in the documentat
 
 @short: finds the item that corresponds to the specified rule
 
-@signature: {'find(rule: object | (item: object, index?: number, array?: object[]) => any): object;'}
+@signature: {'find(rule: object | (item: object, index: number, array: object[]) => any): object;'}
 
 @params:
 - `rule: object | function` - the search criteria:
@@ -17,8 +17,8 @@ description: You can explore the find method of DataCollection in the documentat
         - `match: string` - the value of the item attribute
     - if set as a function, the search will be applied by the rule specified in the function. The function takes three parameters:
         - `item: object` - the object of an item
-        - `index?: number` - optional, the index of an item
-        - `array?: object[]` - optional, an array of items the method was called upon
+        - `index: number` - the index of an item
+        - `array: object[]` - an array of items the method was called upon
 
 @returns:
 The object of the matching item.

docs/data_collection/api/datacollection_findall_method.md

@@ -8,7 +8,7 @@ description: You can explore the findAll method of DataCollection in the documen
 
 @short: finds all the items that correspond to the specified rule
 
-@signature: {'findAll(rule: object | (item: object, index?: number, array?: object[]) => any): object[];'}
+@signature: {'findAll(rule: object | (item: object, index: number, array: object[]) => any): object[];'}
 
 @params:
 - `rule: object | function` - the search criteria:
@@ -17,8 +17,8 @@ description: You can explore the findAll method of DataCollection in the documen
         - `match: string` - the value of the item attribute
     - if set as a function, the search will be applied by the rule specified in the function. The function takes three parameters:
         - `item: object` - the object of an item
-        - `index?: number` - optional, the index of an item
-        - `array?: object[]` - optional, an array of items the method was called upon
+        - `index: number` - the index of an item
+        - `array: object[]` - an array of items the method was called upon
 
 @returns:
 An array of matching item objects.

docs/data_collection/api/datacollection_foreach_method.md

@@ -8,13 +8,13 @@ description: You can explore the forEach method of DataCollection in the documen
 
 @short: iterates over all items of a data collection
 
-@signature: {'forEach(callback: (item: object, index?: number, array?: object[]) => any): void;'}
+@signature: {'forEach(callback: (item: object, index: number, array: object[]) => any): void;'}
 
 @params:
 - `callback: function` - a function that will iterate over items of a data collection. The function is called with the following parameters:
     - `item: object` - the object of an item
-    - `index?: number` - optional, the index of an item
-    - `array?: object[]` - optional, an array of items the method was called upon
+    - `index: number` - the index of an item
+    - `array: object[]` - an array of items the method was called upon
 
 @example:
 component.data.forEach(function (item, index, array) {

docs/data_collection/api/datacollection_load_method.md

@@ -8,7 +8,7 @@ description: You can explore the load method of DataCollection in the documentat
 
 @short: loads data from an external file
 
-@signature: {'load(url: string | DataProxy, driver?: object | string): Promise<any>;'}
+@signature: {'load(url: string | IDataProxy, driver?: object | string): Promise<any>;'}
 
 @params:
 

docs/data_collection/api/datacollection_map_method.md

@@ -8,13 +8,13 @@ description: You can explore the map method of DataCollection in the documentati
 
 @short: iterates through all the items of the component
 
-@signature: {'map(callback: (item: object, index?: number, array?: object[]) => any): object[];'}
+@signature: {'map(callback: (item: object, index: number, array: object[]) => any): object[];'}
 
 @params:
 - `callback: function` - a function that will be called for each item of a component. The function is called with the following parameters:
     - `item: object` - the object of an item
-    - `index?: number` - optional, the index of an item
-    - `array?: object[]` - optional, an array of items the method was called upon
+    - `index: number` - the index of an item
+    - `array: object[]` - an array of items the method was called upon
 
 @returns:
 A new array of items where each item is the result of the callback function.

docs/data_collection/api/datacollection_maprange_method.md

@@ -8,15 +8,15 @@ description: You can explore the mapRange method of DataCollection in the docume
 
 @short: returns a new array of the items according to the specified parameters
 
-@signature: {'mapRange(from: number, to: number, callback: (item: object, index?: number, array?: object[]) => any): object[];'}
+@signature: {'mapRange(from: number, to: number, callback: (item: object, index: number, array: object[]) => any): object[];'}
 
 @params:
 - `from: number` - the initial position of an item in the range
 - `to: number` - the final position of an item in the range
 - `callback: function` - a function that will be called for each item from the specified range. The function is called with the following parameters:
     - `item: object` - the object of an item
-    - `index?: number` - optional, the index of an item
-    - `array?: object[]` - optional, an array of items the method was called upon
+    - `index: number` - the index of an item
+    - `array: object[]` - an array of items the method was called upon
 
 @returns:
 A new array of matching item objects.

docs/data_collection/api/datacollection_reduce_method.md

@@ -8,22 +8,22 @@ description: You can explore the reduce method of DataCollection in the document
 
 @short: reduces the array to a single value
 
-@signature: {'reduce(callback: (acc: any, item: any, index: number) => any, acc: any): any;'}
+@signature: {'reduce(callback: (acc: any, IDataItem: any, index: number) => any, acc: any): any;'}
 
 @params:
 
 - `callback: function` - a function that will be called for each item in the array. The function is called with the following parameters:
     - `acc: any` - the *initialValue*, or the previously returned value of the function
-    - `item: any` - the current item of a data collection
+    - `IDataItem: any` - the current item of a data collection
     - `index: number` - the index of the item 
 - `acc: any` - a value to be passed to the function as the initial value
 
 @returns:
 A single output value.
 
 @example:
-const total = component.data.reduce(function (acc, item, index) {
-    return acc + item.value;
+const total = component.data.reduce(function (acc, IDataItem, index) {
+    return acc + IDataItem.value;
 }, 0);
 
 @descr:

docs/data_collection/api/datacollection_save_method.md

@@ -38,7 +38,7 @@ return data.saveData.then(function () {
 });
 ~~~
 
-Use the [`isSaved`](data_collection/api/datacollection_issaved_method.md) method to know whether the changes are saved:
+Use the [`isSaved`](data_collection/api/datacollection_issaved_method.md) method to check whether the changes are saved:
 
 ~~~jsx
 grid.data.saveData.then(function () {