How to Create BloX Custom 'From-To' Filter -- All Dates with “Clear” Button

Astroraf thanks for the clarification. Please try to use the action code below. It worked for me and the dates did not reset with the page refresh. 

const filVal_from = payload.data.SelectVal_from
const filVal_to = payload.data.SelectVal_to
const filterDims = payload.data.FilterFields;

const dash = payload.widget.dashboard;
let newFilter = {};

newFilter = {
    jaql: {
        dim: "",
        filter: {
            from: filVal_from,
            to: filVal_to
        }
    }
};

filterDims.forEach(function (dim) {
    newFilter.jaql.dim = dim;
    dash.filters.update(newFilter, { refresh: true, save: true })
})

And also add this script to the widget:

widget.on('ready', function() {
	
	// replace with filter name
	var filterName = "Days in Date";

	// ----------Find date filter----------
    let dateFilter = dashboard.filters.$$items.find((item) => {
        if (item.jaql && item.jaql.title.indexOf(filterName) !== -1) {
            return true
        }
    })
	
	
	// ----------Set selected 'from' value as placeholder for input field----------
	var checkInvalid_from = typeof dateFilter.jaql.filter.from == 'undefined' || dateFilter.disabled== true;
	//console.log(dateFilter.jaql.filter.from)
	var filterValue_from = (checkInvalid_from) ? 'date' : dateFilter.jaql.filter.from;

	
	//Set selected 'from' value as placeholder and default value for input field
	//$('#SelectVal_from', element).attr('placeholder', filterValue_from);
	$('#SelectVal_from', element).attr('value', filterValue_from);
	
	
	// ----------Set selected 'to' value as placeholder for input field----------
	var checkInvalid_to = typeof dateFilter.jaql.filter.to == 'undefined' || dateFilter.disabled== true;
	//console.log(dateFilter.jaql.filter.to)
	var filterValue_to = (checkInvalid_to) ? 'date' : dateFilter.jaql.filter.to;
	
	//Set selected 'to' value as placeholder and default value for input field
	//$('#SelectVal_to', element).attr('placeholder', filterValue_to);
	$('#SelectVal_to', element).attr('value', filterValue_to);	
	
	
	
});

Best Regards, Lily