Bucket numeric fields into regular fixed-width intervals for charts and sidebar facets.

Histogram Aggregation

histogram(interval) groups numeric values into regular fixed-width buckets.

Basic usage

const priceIndex = index.getFieldIndex("price") as NumericFieldIndex;
const buckets = priceIndex.histogram(10);

Expected shape:

[
  { key: 0, docCount: 4 },
  { key: 10, docCount: 9 },
  { key: 20, docCount: 3 }
]

Each key is the start of the bucket.

With an interval of 10:

Buckets use document-count semantics, so a document contributes once per bucket even if multiple values fall inside the same bucket.

const subsetBuckets = priceIndex.histogram(10, new Set(["a", "b"]));