@kbn/field-formats-common

Common pieces shared by field formatters across Kibana.

This tiny package centralizes a few labels/tokens that are used consistently when formatting values in tables, charts, and other UI components.

Exports

The package currently exposes the following constants from ./constants:

• EMPTY_LABEL — i18n label for empty string values. Default: "(blank)"
• NULL_LABEL — i18n label for null values. Default: "(null)"
• NAN_LABEL — string used to represent Not-a-Number. Value: "NaN"
• MISSING_TOKEN — internal token used to mark missing values in aggregations and formatting flows. Value: "__missing__"

Usage

Import the constants and use them when rendering or formatting values so the UI stays consistent across apps and plugins.

import { EMPTY_LABEL, NULL_LABEL, NAN_LABEL, MISSING_TOKEN } from '@kbn/field-formats-common';

function renderCell(value: unknown) {
	if (value === null) return NULL_LABEL;
	if (value === '') return EMPTY_LABEL;
	if (Number.isNaN(value)) return NAN_LABEL;
	return String(value);
}

// Example: handling "missing" buckets from aggregations
function normalizeBucketKey(key: string | undefined) {
	return key === undefined ? MISSING_TOKEN : key;
}

Notes

• EMPTY_LABEL and NULL_LABEL are i18n-aware strings; they should be used directly in UI output.
• MISSING_TOKEN is an internal sentinel value, not a user-facing label; prefer mapping it to a label (for example, EMPTY_LABEL) before rendering.
• If you need to customize how special values are displayed, build that logic on top of these shared constants rather than re-defining literals.