Custom Filter

Description

You can also create your own Custom Filter with any html/css you want and/or jQuery library you wish to use. Angular template (component) are not supported at this point, if you wish to contribute on that end then I certainly accept PR (Pull Request).

Limitations

• as mentioned in the description, only html/css and/or jQuery libraries are supported.
  • this mainly mean that Angular templates (components) are not supported (feel free to contribute).
• SlickGrid uses table-cell as CSS for it to display a consistent height for each rows (this keeps the same row height/line-height to always be the same).
  • all this to say that you might be in a situation were your filter shows in the back of the grid. The best approach to overcome this is to use a modal if you can or if the library support append to body container. For example, you can see that multiple-select.js support a container and is needed for the filter to work as can be seen in the multipleSelectFilter.ts

Demo

Demo Page / Demo Component

How to use Custom Filter?

1. You first need to create a class using the Filter interface. Make sure to create all necessary public properties and functions.

• You can see a demo with a custom-inputFilter.ts that is used in the demo - example 4

2. Simply set the filter type to FilterType.custom and instantiate your class with new (can also pass DI in the constructor if you wish). Here is an example with a custom input filter:

// define you columns, in this demo Effort Driven will use a Select Filter
this.columnDefinitions = [      
  { id: 'title', name: 'Title', field: 'title' },
  { id: 'description', name: 'Description', field: 'description', type: FieldType.string,
    filterable: true, 
    filter: {
       type: FilterType.custom,
       customFilter: new CustomInputFilter() // create a new instance to make each Filter independent from each other
    }
  }
];

// you also need to enable the filters in the Grid Options
this.gridOptions = {
   enableFiltering: true
};

Collection

If you want to pass a collection to your filter (for example, a multiple-select needs a select list of options), you can then use it in your custom filter through columnDef.filter.collection

Default Search Term(s)

If you want to load the grid with certain default filter(s), you can use the following optional properties:

• searchTerm (single value) with singleSelect or select
• searchTerms (array of values) with multipleSelect

For example, setting a default value into an input element, you can simply get the search term with columnDef.filter.searchTerm and set the default value in jquery with $(filterElm).val(this.searchTerm);

How to add Translation?

LabelKey

By default a collection uses the label/value pair without translation or labelKey/value pair with translation usage. So if you want to use translations, then you can loop through your collection and use the labelKey/value properties. For example:

this.columnDef.filter.collection.forEach((option: SelectOption) => {
  // translate label      
  const textLabel = (option.labelKey && typeof this.translate.instant === 'function') ? this.translate.instant(option.labelKey || ' ') : option.labelKey;

  // use the option value & translated label
  options += `<option value="${option.value}">${textLabel}</option>`;
});

Custom Structure (key/label pair)

What if your collection have totally different value/label pair? In this case, you can use the customStructure to change the property name(s) to use. You can change the label and/or the value, they can be passed independently. For example:

// use custom structure value/label pair
const labelName = (this.columnDef.filter.customStructure) ? this.columnDef.filter.customStructure.label : 'label';
const valueName = (this.columnDef.filter.customStructure) ? this.columnDef.filter.customStructure.value : 'value';

this.columnDef.filter.collection.forEach((option: SelectOption) => {
  // use the option value & translated label
  options += `<option value="${option[valueName]}">${option[labelName]}</option>`;
});

Custom Structure with Translation

What if you want to use customStructure and translate the labels? Simply pass the flag enableTranslateLabel: true

For example:

// use custom structure value/label pair
const labelName = (this.columnDef.filter.customStructure) ? this.columnDef.filter.customStructure.label : 'label';
const valueName = (this.columnDef.filter.customStructure) ? this.columnDef.filter.customStructure.value : 'value';

this.columnDef.filter.collection.forEach((option: SelectOption) => {
  // translate label      
  const textLabel = (option.labelKey && typeof this.translate.instant === 'function') ? this.translate.instant(option[labelName] || ' ') : option[labelName];

  // use the option value & translated label
  options += `<option value="${option[valueName]}">${textLabel}</option>`;
});