[v7] useSort - Multisort functionality: Limit max cols and optional shift key (#1433)

* [v7] useSort - Multisort functionality: Limit `multiSort` number and configurable shift key

1. Provide configuration for multisort that pressing shift key is not compulsory

2. Configurable limit on max number of columns for multisort, like configuration has been provided that `maxMultiSortColCount` is 3, suppose currenlty table is sorted by `[A, B, C]` and then clicking `D` for sorting should result in table sorted by `[B, C , D]`

* update readme for new multisort options

* Use `isMultiSortEvent` function 

so as to make `shift` key optional or take decision based on other parameters for multisorting

* `isMultiSortEvent` updated readme

README.md

@@ -587,6 +587,11 @@ The following options are supported via the main options object passed to `useTa
   - Disables sorting for every column in the entire table.
 - `disableMultiSort: Bool`
   - Disables multi-sorting for the entire table.
+- `isMultiSortEvent: Function`
+  - Allows to override default multisort behaviour(i.e. multisort applies when shift key is presssed), if this function is provided then returned boolean value from this function will make decision whether newly applied sort action will be considered as multisort or not.
+  - Receives `event` as argument.
+- `maxMultiSortColCount: Number`
+  - Limit on max number of columns for multisort, e.g. if set to 3, and suppose table is sorted by `[A, B, C]` and then clicking `D` for sorting should result in table sorted by `[B, C , D]`
 - `disableSortRemove: Bool`
   - If true, the un-sorted state will not be available to columns once they have been sorted.
 - `disableMultiRemove: Bool`

src/plugin-hooks/useSortBy.js

@@ -31,6 +31,8 @@ const propTypes = {
   manualSorting: PropTypes.bool,
   disableSorting: PropTypes.bool,
   disableMultiSort: PropTypes.bool,
+  isMultiSortEvent: PropTypes.func,
+  maxMultiSortColCount: PropTypes.number, 
   disableSortRemove: PropTypes.bool,
   disableMultiRemove: PropTypes.bool,
 }
@@ -55,6 +57,8 @@ function useMain(instance) {
     disableSortRemove,
     disableMultiRemove,
     disableMultiSort,
+    isMultiSortEvent = (e) => e.shiftKey,
+    maxMultiSortColCount = Number.MAX_SAFE_INTEGER,
     hooks,
     state: [{ sortBy }, setState],
     plugins,
@@ -128,6 +132,8 @@ function useMain(instance) {
             desc: hasDescDefined ? desc : sortDescFirst,
           },
         ]
+        // Take latest n columns
+        newSortBy.splice(0, newSortBy.length - maxMultiSortColCount);
       } else if (action === 'toggle') {
         // This flips (or sets) the
         newSortBy = sortBy.map(d => {
@@ -177,7 +183,7 @@ function useMain(instance) {
                 e.persist()
                 column.toggleSortBy(
                   undefined,
-                  !instance.disableMultiSort && e.shiftKey
+                  !instance.disableMultiSort && isMultiSortEvent(e)
                 )
               }
             : undefined,