Highlight - Settings

[GlennRicaud]

To be PRed in branch epic-highlight

Add capability to specify settings for the highlight
Settings can be set globally for all fields or by field (Then they override the global settings)

var result = repo.query({
        query: "displayName = 'Mine båter'",
        highlight: {
            "preTag" : "<a>",
            "fields": {
                "displayName": {
                    "preTag" : "<b>"
                }
            }
        }
    });

Add the following highlight settings

• encoder
• fragmenter
• fragment_size
• no_match_size
• number_of_fragments
• order
• pre_tags
• post_tags
• require_field_match
• tags_schema

Useful links:
Highlighting doc for current version: https://www.elastic.co/guide/en/elasticsearch/reference/2.4/search-request-highlighting.html
Listing of parameters for latest version of ES
https://www.elastic.co/guide/en/elasticsearch/reference/7.x/search-request-body.html#request-body-search-highlighting

[GlennRicaud]

Little bug when unboxing parameters -> Fixed
Also noMatchSize should not have a default value I think -> Fixed
Fixed typo fragmenterSize to fragmentSize

Also there is a bug in ES: elastic/elasticsearch#9442
So "fragmentSize" works but only when selection the fragmenter "simple"

Below is the list of settings when using the JS lib
//Global
encoder
tagsSchema
//Global and field specific
fragmenter
fragmenterSize
noMatchSize
numberOfFragments
order
preTag
postTag
requireFieldMatch

Possible values:
encoder: 'default' (default) | 'html'
tagsSchema: 'styled' | null (default)
fragmenter: 'simple' | 'span' (default)
fragmentSize: integer (default:100) //See comment above
noMatchSize: integer (default:0)
numberOfFragments: integer (default:5)
order: "score" | "none" (default) //Did not manage to test this yet
preTag: string
postTag: string
requireFieldMatch: boolean (default: true)