Module @metreeca/keep-flake - v0.12.2

Shape-driven traversal trees.

A Shape and its retrieval template or collection query scatter what to fetch across independent probes: property requests, constraints, and transforms. A flake gathers those probes into one traversal tree. A connector walks that tree directly, instead of matching the raw shape against the raw input at every step.

Three flavours of the tree are available:

shape — the full structural reach of a resource shape, with no input, built by createFlake;
model — the reach restricted to the properties a retrieval template addresses, each node carrying the drain requested for it, built by createFlake;
query — a collection member shape tagged with the constraints, ordering, and projections a collection query expresses, built by createQueryFlake.

Every node, the root included, is a Flake. Its path locates it along the property axis and its pipe along the transform axis. A resource node branches along both axes, while a non-resource node is a bare leaf:

property branches — a node steps through its entries into one Branch per addressed Id / Type / Property; a name shared by several variants of a union-typed node takes a single branch;
transform stages — a node holds each Transform a query applies to it as a nested Flake under its transforms.

Type Aliases

Flake: A node of a flake.
Branch: Property-step node of a flake.
Drain: The retrieval requested at a node of a flake.
Transforms: A node's transform stages, keyed by the Transform each stage applies.
Entries: A node's property branches, keyed by property name.

Functions

createFlake: Builds a Flake from a Shape and an optional retrieval template.
createQueryFlake: Builds a flake from a collection's member shape and the query retrieving it.
isComputedFlake: Checks whether a Flake is a transform stage rather than a property or marker step.
isAggregateFlake: Checks whether a Flake is an aggregate transform stage.
isScalarFlake: Checks whether a Flake is a scalar (non-aggregating) transform stage.
isGroupingFlake: Checks whether a Flake groups the query.
isDrainedFlake: Checks whether a Flake requests any retrieval, at the node or anywhere beneath it.
isConstrainedFlake: Checks whether a Flake carries any constraint, ranking, or ordering slot, at the node or anywhere beneath it.
isFilteredFlake: Checks whether a Flake carries a filtering constraint, at the node or anywhere beneath it.
isRequiredFlake: Checks whether a Flake carries an existence-implying filter constraint, at the node or anywhere beneath it.
hasValueOptions: Checks whether a Flake's set matching constraints name at least one non-null value.
hasDictionaryOptions: Checks whether a Flake's set matching constraints include a localised dictionary option.
hasNullOptions: Checks whether a Flake's set matching constraints include an explicit null option.
isBranch: Checks whether a Flake is a Branch, that is a property or marker step whose entry is available.
isPropertyBranch: Checks whether a flake steps through a Property edge, regardless of what it retrieves: the union of model, query, and projected branches, excluding Id / Type markers and transform stages.
isModelBranch: Checks whether a flake steps through a single-valued Property, whose retrieval addresses one value and admits no collection constraints.
isQueryBranch: Checks whether a flake steps through a multi-valued Property, whose retrieval addresses a collection and carries the criteria narrowing it.
isProbeBranch: Checks whether a flake is projected by a query: its drain carries a projection alias.
getFlakeProjections: Collects every projected flake of a Flake into a flat list.
getFlakeTransforms: Lists a flake's own transform stages.
getFlakeEntries: Lists a flake's own property branches.
getFlakeProjection: Collects every projection in a Flake into an alias-keyed index.
getFlakeGrouping: Collects the grouping keys of a Flake.
getFlakeFocusing: Collects the focus keys of a Flake.
getFlakeOrdering: Collects the sort keys of a Flake, by ascending precedence.
getFlakeVariant: Selects the property branches of a node that one variant of its range declares.

Module @metreeca/keep-flake - v0.12.2

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