Field Types

A field definition can include four types of information:

  • The name of the field type (mandatory)
  • Type of the field (defaults to Text)
  • Information about the associated search and index time analyzers (defaults to StandardAnalyzer)
  • Field type properties - depends on the FieldType.

Below is a sample Field definition from the index.json file.

      "allowSort": false,
      "fieldName": "b1",
      "fieldType": "Bool",
      "indexAnalyzer": "standard",
      "searchAnalyzer": "standard",
      "similarity": "TFIDF"
Property NameDescription
AllowSortEnables a field for sorting. Behind the scene a new docvalues field is created with the same name which is used for sorting.
IndexAnalyzerAnalyzer to be used during index time
SearchAnalyzerAnalyzer to be used during search time
SimilarityA field may optionally specify a similarity that will be used when scoring documents.

As Lucene index back-compatibility is only supported for the default codec. We took a conscious decision to hide codec level settings at the field level. Technically it is possible to have per field postings format and docvalues format. Currently FlexSearch only allows configuring Bloom Filter on the id field.

Field Types

The field type defines how FlexSearch should interpret data in a field and how the field can be queried. There are many field types included with FlexSearch by default which should cover most of the cases. The below table list the various field types supported by FlexSearch.

Field TypeDescription
KeywordField to store keywords. The entire input will be treated as a single word. This is useful for fields like customerid, referenceid etc. These fields only support complete text matching while searching and no partial word match is available.
TextGeneral purpose field to store normal textual data. This also supports text highlighting.
BoolBoolean (Internally the values are saved as ‘T’ and ‘F’ to save space)
DateFixed format date field (Supported format: YYYYmmdd)
DateTimeFixed format datetime field (Supported format: YYYYMMDDhhmmss)
StoredNon-indexed field. Only used for retrieving stored text. Searching is not possible over these fields.