JavaScript ChartsSecondary Axes

Secondary axes are typically used to compare data sets with different scales, where extra y-axes are usually located on the opposite side of the chart.

Configuring Secondary Axes

For each secondary axis an axis configuration is required to associate the axis with the appropriate series using the keys axis property. A sample configuration is shown below:

An extra axis configuration is needed to associate a secondary axis with a given series, where the keys axis property links the appropriate series to the axis. A sample configuration is shown below:

axes: [
    // x-axis
    {
        type: "category",
        position: "bottom",
    },
    // primary y-axis
    {
        type: "number",
        position: "left",
        keys: ["male", "female"],
    },
    // secondary y-axis
    {
        type: "number",
        position: "right",
        keys: ["exportedTonnes"],
    }
]

In the snippet above, a secondary y-axis is positioned to the right of the chart showing the exportedTonnes.

The following example demonstrates a secondary y-axis. Note the following:

The axis keys property on the primary axis (left) matches the yKeys of the column series.
The axis keys property on the secondary axis (right) matches the yKey of the line series.

Example: Secondary y-axis