data-structures.md

title
Data structures

The data property of a dataset can be passed in various formats. By default, that data is parsed using the associated chart type and scales.

Primitive[]

data: [20, 10],
labels: ['a', 'b']

When the data is an array of numbers, values from labels array at the same index are used for the index axis (x for vertical, y for horizontal charts).

Object[]

data: [{x: 10, y: 20}, {x: 15, y: 10}]

data: [{x:'2016-12-25', y:20}, {x:'2016-12-26', y:10}]

data: [{x:'Sales', y:20}, {x:'Revenue', y:10}]

This is also the internal format used for parsed data. In this mode, parsing can be disabled by specifying parsing: false at chart options or dataset. If parsing is disabled, data must be sorted and in the formats the associated chart type and scales use internally.

Object[] using custom properties

type: 'bar',
data: {
    datasets: [{
        data: [{id: 'Sales', nested: {value: 1500}}, {id: 'Purchases', nested: {value: 500}}]
    }]
},
options: {
    parsing: {
        xAxisKey: 'id',
        yAxisKey: 'nested.value'
    }
}

parsing can also be specified per dataset

const data = [{x: 'Jan', net: 100, cogs: 50, gm: 50}, {x: 'Feb', net: 120, cogs: 55, gm: 75}];
const cfg = {
    type: 'bar',
    data: {
        labels: ['Jan', 'Feb'],
        datasets: [{
            label: 'Net sales',
            data: data,
            parsing: {
                yAxisKey: 'net'
            }
        }, {
            label: 'Cost of goods sold',
            data: data,
            parsing: {
                yAxisKey: 'cogs'
            }
        }, {
            label: 'Gross margin',
            data: data,
            parsing: {
                yAxisKey: 'gm'
            }
        }]
    },
};

Object

data: {
    January: 10,
    February: 20
}

In this mode, property name is used for index scale and value for value scale. For vertical charts, index scale is x and value scale is y.