How to convert an array into columns in an Excel web add-in?

I want to take an object as two columns of a selected table. How can I extract a selected column and pass it as an object? I want the barData object to be the selected columns. This code creates a graph on the add-in taskpane on clicking a button which calls the function. Here is my code:

home.html

<svg id="visualisation" width="1000" height="500"></svg>

home.js

   function InitChart() {

        var barData = [{
            'x': 1,
            'y': 5
        }, {
            'x': 20,
            'y': 20
        }, {
            'x': 40,
            'y': 10
        }, {
            'x': 60,
            'y': 40
        }, {
            'x': 80,
            'y': 5
        }, {
            'x': 100,
            'y': 60
        }];

        var vis = d3.select('#visualisation'),
            WIDTH = 1000,
            HEIGHT = 500,
            MARGINS = {
                top: 20,
                right: 20,
                bottom: 20,
                left: 50
            },
            xRange = d3.scale.ordinal().rangeRoundBands([MARGINS.left, WIDTH - MARGINS.right], 0.1).domain(barData.map(function (d) {
                return d.x;
            })),


            yRange = d3.scale.linear().range([HEIGHT - MARGINS.top, MARGINS.bottom]).domain([0,
                d3.max(barData, function (d) {
                    return d.y;
                })
            ]),

            xAxis = d3.svg.axis()
                .scale(xRange)
                .tickSize(5)
                .tickSubdivide(true),

            yAxis = d3.svg.axis()
                .scale(yRange)
                .tickSize(5)
                .orient("left")
                .tickSubdivide(true);


        vis.append('svg:g')
            .attr('class', 'x axis')
            .attr('transform', 'translate(0,' + (HEIGHT - MARGINS.bottom) + ')')
            .call(xAxis);

        vis.append('svg:g')
            .attr('class', 'y axis')
            .attr('transform', 'translate(' + (MARGINS.left) + ',0)')
            .call(yAxis);

        vis.selectAll('rect')
            .data(barData)
            .enter()
            .append('rect')
            .attr('x', function (d) {
                return xRange(d.x);
            })
            .attr('y', function (d) {
                return yRange(d.y);
            })
            .attr('width', xRange.rangeBand())
            .attr('height', function (d) {
                return ((HEIGHT - MARGINS.bottom) - yRange(d.y));
            })
            .attr('fill', 'grey')
            .on('mouseover', function (d) {
                d3.select(this)
                    .attr('fill', 'blue');
            })
            .on('mouseout', function (d) {
                d3.select(this)
                    .attr('fill', 'grey');
            });

    }