[Bug]: Tooltip Formatter Not Called When value is Falsey

[roccomaniscalco]

Relevant package(s)

• @carbon/charts
• @carbon/charts-svelte
• @carbon/charts-react
• @carbon/charts-angular
• @carbon/charts-vue
• Documentation website

Carbon Charts Version

1.22.0

Which bundler are you using?

Vite

What happened and what did you expect to happen?

tooltip.valueFormatter is not called when the value argument is falsey. This is an issue when value is 0.

Say we want to add "units" to all y-values in our tooltip:

valueFormatter: (value, label) => {
  if (label === 'y-value') {
    return value + ' units';
  }
}

We will only see "units" added to non-falsey values:

I believe the issue is being caused by this condition:

carbon-charts/packages/core/src/components/essentials/tooltip.ts

Line 169 in d602884

item.value = item.value ? this.valueFormatter(item.value, item.label) : item.value

Chart data and options (automatically formatted so no need for backticks)

// options
{
  title: 'Vertical simple bar (discrete)',
  axes: {
    left: {
      mapsTo: 'value',
    },
    bottom: {
      mapsTo: 'group',
      scaleType: 'labels',
    },
  },
  height: '400px',
  tooltip: {
    // when value is 0, `valueFormatter` isn't executed
    valueFormatter: (value, label) => {
      if (label === 'y-value') {
        return value + ' units';
      }
    },
  },
};

// data
[
  {
    group: 'Qty',
    value: 0
  },
  {
    group: 'More',
    value: 29123
  },
  {
    group: 'Sold',
    value: 35213
  },
  {
    group: 'Restocking',
    value: 51213
  },
  {
    group: 'Misc',
    value: 16932
  }
]

JavaScript console or build output (if relevant)

StackBlitz repro

https://stackblitz.com/edit/juzzbq?file=options.js,data.js

IBM Application/Team (if relevant)

No response

What priority level would this be in your opinion?

P3 (Low)