Bmg.js Public API

Public API available via import { ... } from '@enspirit/bmg-js'.

Factory & Constants

Export	Description
`Bmg(tuples)`	Factory to create relations from arrays
`Bmg.isRelation(value)`	Type guard for relations
`DEE`	Relation with no attributes, one tuple (identity for join)
`DUM`	Relation with no attributes, no tuples (identity for union)
`LIB_DEFINITIONS`	TypeScript definitions string (for playgrounds)

Export	Description
`toText(input, options?)`	Render relation/tuple as ASCII table
`isRelation(value)`	Type guard for relations
`isEqual(left, right)`	Check set equality of two relations

All operators work on arrays and return arrays:

Category	Operators
Filtering	`restrict`, `where`, `exclude`
Projection	`project`, `allbut`
Extension	`extend`, `constants`
Renaming	`rename`, `prefix`, `suffix`
Set ops	`union`, `minus`, `intersect`
Semi-joins	`matching`, `not_matching`
Joins	`join`, `left_join`, `cross_product`
Nesting	`group`, `ungroup`, `wrap`, `unwrap`, `image`, `summarize`, `autowrap`
Transform	`transform`
Terminal	`one`, `yByX`

All operators above are also available as chainable methods on relations:

const result = Bmg(suppliers)
  .restrict({ city: 'London' })
  .project(['sid', 'name'])
  .toArray();

Additional methods on Relation<T>:

Core: Tuple, AttrName, Relation, RelationOperand

Predicates: Predicate, TypedPredicate

Extensions: Extension, TypedExtension

Joins: JoinKeys, TypedJoinKeysArray, TypedJoinKeysObject

Aggregation: Aggregator, Aggregators, AggregatorName, AggregatorSpec

Options: TextOptions, AutowrapOptions, PrefixOptions, SuffixOptions, GroupOptions, WrapOptions

Utility types: Renamed, Prefixed, Suffixed, Joined, LeftJoined, Wrapped, Unwrapped, Ungrouped, CommonKeys