resize_columns.js

var ResizeColumns = function(table){
    this.table = table; //hold Tabulator object
    this.startColumn = false;
    this.startX = false;
    this.startWidth = false;
    this.handle = null;
    this.prevHandle = null;
};

ResizeColumns.prototype.initializeColumn = function(type, column, element){
    var self = this,
    variableHeight =false,
    mode = this.table.options.resizableColumns;

    //set column resize mode
    if(type === "header"){
        variableHeight = column.definition.formatter == "textarea" || column.definition.variableHeight;
        column.modules.resize = {variableHeight:variableHeight};
    }

    if(mode === true || mode == type){

        var handle = document.createElement('div');
        handle.className = "tabulator-col-resize-handle";


        var prevHandle = document.createElement('div');
        prevHandle.className = "tabulator-col-resize-handle prev";

        handle.addEventListener("click", function(e){
            e.stopPropagation();
        });

        var handleDown = function(e){
            var nearestColumn = column.getLastColumn();

            if(nearestColumn && self._checkResizability(nearestColumn)){
                self.startColumn = column;
                self._mouseDown(e, nearestColumn, handle);
            }
        };

        handle.addEventListener("mousedown", handleDown);
        handle.addEventListener("touchstart", handleDown, {passive: true});

        //reszie column on  double click
        handle.addEventListener("dblclick", function(e){
            var col = column.getLastColumn();

            if(col && self._checkResizability(col)){
                e.stopPropagation();
                col.reinitializeWidth(true);
            }
        });


        prevHandle.addEventListener("click", function(e){
            e.stopPropagation();
        });

        var prevHandleDown = function(e){
            var nearestColumn, colIndex, prevColumn;

            nearestColumn = column.getFirstColumn();

            if(nearestColumn){
                colIndex = self.table.columnManager.findColumnIndex(nearestColumn);
                prevColumn = colIndex > 0 ? self.table.columnManager.getColumnByIndex(colIndex - 1) : false;

                if(prevColumn && self._checkResizability(prevColumn)){
                    self.startColumn = column;
                    self._mouseDown(e, prevColumn, prevHandle);
                }
            }
        };

        prevHandle.addEventListener("mousedown", prevHandleDown);
        prevHandle.addEventListener("touchstart", prevHandleDown, {passive: true});

        //resize column on double click
        prevHandle.addEventListener("dblclick", function(e){
            var nearestColumn, colIndex, prevColumn;

            nearestColumn = column.getFirstColumn();

            if(nearestColumn){
                colIndex = self.table.columnManager.findColumnIndex(nearestColumn);
                prevColumn = colIndex > 0 ? self.table.columnManager.getColumnByIndex(colIndex - 1) : false;

                if(prevColumn && self._checkResizability(prevColumn)){
                    e.stopPropagation();
                    prevColumn.reinitializeWidth(true);
                }
            }
        });

        element.appendChild(handle);
        element.appendChild(prevHandle);
    }
};


ResizeColumns.prototype._checkResizability = function(column){
    return typeof column.definition.resizable != "undefined" ? column.definition.resizable : this.table.options.resizableColumns;
};

ResizeColumns.prototype._mouseDown = function(e, column, handle){
    var self = this;

    self.table.element.classList.add("tabulator-block-select");

    function mouseMove(e){
        // self.table.columnManager.tempScrollBlock();

        column.setWidth(self.startWidth + ((typeof e.screenX === "undefined" ? e.touches[0].screenX : e.screenX) - self.startX));

        if(!self.table.browserSlow && column.modules.resize && column.modules.resize.variableHeight){
            column.checkCellHeights();
        }
    }

    function mouseUp(e){

        //block editor from taking action while resizing is taking place
        if(self.startColumn.modules.edit){
            self.startColumn.modules.edit.blocked = false;
        }

        if(self.table.browserSlow && column.modules.resize && column.modules.resize.variableHeight){
            column.checkCellHeights();
        }

        document.body.removeEventListener("mouseup", mouseUp);
        document.body.removeEventListener("mousemove", mouseMove);

        handle.removeEventListener("touchmove", mouseMove);
        handle.removeEventListener("touchend", mouseUp);

        self.table.element.classList.remove("tabulator-block-select");

        if(self.table.options.persistence && self.table.modExists("persistence", true) && self.table.modules.persistence.config.columns){
            self.table.modules.persistence.save("columns");
        }

        self.table.options.columnResized.call(self.table, column.getComponent());
    }

    e.stopPropagation(); //prevent resize from interfereing with movable columns

    //block editor from taking action while resizing is taking place
    if(self.startColumn.modules.edit){
        self.startColumn.modules.edit.blocked = true;
    }

    self.startX = typeof e.screenX === "undefined" ? e.touches[0].screenX : e.screenX;
    self.startWidth = column.getWidth();

    document.body.addEventListener("mousemove", mouseMove);
    document.body.addEventListener("mouseup", mouseUp);
    handle.addEventListener("touchmove", mouseMove, {passive: true});
    handle.addEventListener("touchend", mouseUp);
};

Tabulator.prototype.registerModule("resizeColumns", ResizeColumns);