Should render suggestions - AutocompleteArrayInput

docs/Inputs.md

@@ -289,6 +289,9 @@ By default the component matches choices with the current input searchText. For
 
 If you want to limit the initial choices shown to the current value only, you can set the `limitChoicesToValue` prop.
 
+When dealing with a large amount of `choices` you may need to limit the number of suggestions that are rendered in order to maintain usable performance. The `shouldRenderSuggestions` is an optional prop that allows you to set conditions on when to render suggestions. An easy way to improve performance would be to skip rendering until the user has entered 2 or 3 characters in the search box. This lowers the result set significantly, and might be all you need (depending on your data set). 
+Ex. `<AutocompleteArrayInput shouldRenderSuggestions={(val) => { return val.trim().length > 2 }} />` would not render any suggestions until the 3rd character was entered. This prop is passed to the underlying `react-autosuggest` component and is documented [here](https://github.com/moroshko/react-autosuggest#should-render-suggestions-prop).
+
 Lastly, `<AutocompleteArrayInput>` renders a [material-ui-chip-input](https://github.com/TeamWertarbyte/material-ui-chip-input) component. Use the `options` attribute to override any of the `<ChipInput>` attributes:
 
 {% raw %}
@@ -326,6 +329,7 @@ import { AutocompleteArrayInput, ReferenceArrayInput } from 'react-admin'
 | `optionText` | Optional | <code>string &#124; Function</code> | `name` | Fieldname of record to display in the suggestion item or function which accepts the current record as argument (`(record)=> {string}`) |
 | `setFilter` | Optional | `Function` | null | A callback to inform the `searchText` has changed and new `choices` can be retrieved based on this `searchText`. Signature `searchText => void`. This function is automatically setup when using `ReferenceInput`.  |
 | `suggestionComponent` | Optional | Function | `({ suggestion, query, isHighlighted, props }) => <div {...props} />` | Allows to override how the item is rendered.  |
+| `shouldRenderSuggestions` | Optional | Function | `() => true` | A function that returns a `boolean` to determine whether or not suggestions are rendered. Use this when working with large collections of data to improve performance and user experience. This function is passed into the underlying react-autosuggest component. Ex.`(value) => value.trim() > 2` |
 
 ## `<BooleanInput>` and `<NullableBooleanInput>`
 

packages/ra-ui-materialui/src/input/AutocompleteArrayInput.js

@@ -419,7 +419,14 @@ export class AutocompleteArrayInput extends React.Component {
         this.previousFilterValue = value;
     };
 
-    shouldRenderSuggestions = () => true;
+    shouldRenderSuggestions = (val) => {
+        const { shouldRenderSuggestions } = this.props;
+        if (shouldRenderSuggestions !== undefined && typeof shouldRenderSuggestions === 'function') {
+          return shouldRenderSuggestions(val)
+        }
+
+        return true
+    };
 
     render() {
         const {
@@ -495,6 +502,7 @@ AutocompleteArrayInput.propTypes = {
     optionValue: PropTypes.string.isRequired,
     resource: PropTypes.string,
     setFilter: PropTypes.func,
+    shouldRenderSuggestions: PropTypes.func,
     source: PropTypes.string,
     suggestionComponent: PropTypes.func,
     translate: PropTypes.func.isRequired,

packages/ra-ui-materialui/src/input/AutocompleteArrayInput.spec.js

@@ -164,6 +164,30 @@ describe('<AutocompleteArrayInput />', () => {
         assert.equal(MenuItem.text(), 'Male');
     });
 
+    it('should respect shouldRenderSuggestions over default if passed in', () => {
+        const wrapper = mount(
+            <AutocompleteArrayInput
+                {...defaultProps}
+                input={{ value: ['M'], onChange: () => {} }}
+                choices={[{ id: 'M', name: 'Male' }]}
+                shouldRenderSuggestions={v => v.length > 2}
+            />,
+            { context, childContextTypes }
+        );
+        wrapper.find('input').simulate('focus');
+        wrapper
+            .find('input')
+            .simulate('change', { target: { value: 'Ma' } });
+        expect(wrapper.state('suggestions')).toHaveLength(1);
+        expect(wrapper.find('ListItem')).toHaveLength(0);
+
+        wrapper
+            .find('input')
+            .simulate('change', { target: { value: 'Mal' } });
+        expect(wrapper.state('suggestions')).toHaveLength(1);
+        expect(wrapper.find('ListItem')).toHaveLength(1);
+    });
+
     describe('Fix issue #1410', () => {
         it('should not fail when value is empty and new choices are applied', () => {
             const wrapper = shallow(