The Weight Tracker is a Script API showcase present in the demo notes.

By adding weight as a promoted attribute in the template from which day notes are created, you can aggregate the data and plot weight change over time.

Implementation

The Weight Tracker note in the screenshot above is of the type Render Note. That type of note doesn't have any useful content itself. Instead it is a placeholder where a script can render its output.

Scripts for Render Notes are defined in a relation called ~renderNote. In this example, it's the Weight Tracker's child Implementation. The Implementation consists of two code notes that contain some HTML and JavaScript respectively, which load all the notes with a weight attribute and display their values in a chart.

To actually render the chart, we're using a third party library called chart.jswhich is imported as an attachment, since it's not built into Trilium.

Code

Here's the content of the script which is placed in a code note of type JS Frontend:

async function getChartData() {
    const days = await api.runOnBackend(async () => {
        const notes = api.getNotesWithLabel('weight');
        const days = [];

        for (const note of notes) {
            const date = note.getLabelValue('dateNote');
            const weight = parseFloat(note.getLabelValue('weight'));

            if (date && weight) {
                days.push({ date, weight });
            }
        }

        days.sort((a, b) => a.date > b.date ? 1 : -1);

        return days;
    });

    const datasets = [
        {
            label: "Weight (kg)",
            backgroundColor: 'red',
            borderColor: 'red',
            data: days.map(day => day.weight),
            fill: false,
            spanGaps: true,
            datalabels: {
                display: false
            }
        }
    ];

    return {
        datasets: datasets,
        labels: days.map(day => day.date)
    };
}

const ctx = $("#canvas")[0].getContext("2d");

new chartjs.Chart(ctx, {
    type: 'line',
    data: await getChartData()
});

How to remove the Weight Tracker button from the top bar

In the link map of the Weight Tracker, there is a note called Button. Open it and delete or comment out its contents. The Weight Tracker button will disappear after you restart Trilium.