js_colorgenerator

    function getColorSets(){
        const numberRange = [...Array( 14).keys()].map( x => x * 20)		// [0,20..260]
        const addZero = function( val){ return ( val.length < 2) ? "0" + val : val; }
        const defaultColors = ["f44336","E91E63","9C27B0","673AB7","3F51B5","2196F3","03A9F4","00BCD4","009688",
        "4CAF50","8BC34A","CDDC39","FFEB3B","FFC107","FF9800","FF5722","795548","9E9E9E","607D8B"]
        const flattenList = function( unFlattenedList){ [].concat.apply([], unFlattenedList) }
        const generateSet = function( colors, n) {
            return colors.map( x => [[x.slice(0,2)],[x.slice(2,4)],[x.slice(4,6)]])         // slice RGB
            			 .map(x => x.map( d => addZero( ( ( parseInt( d, 16) + n) % 255).toString( 16))))
            			 .map( x => x.join( ""))
            			 .map( x => "#"+x)
        }
        return flattenList( numberRange.map( x => generateSet( defaultColors, x)))
    }