geospatial-sdk / core/lib / computeMapContextDiff

computeMapContextDiff()

function computeMapContextDiff(nextContext, previousContext): MapContextDiff

The following logic is produced by identifying layers in both context and determining whether they have been added, removed, changed or reordered.

Identifying layers to determine if they have been added/removed/reordered is done like so:

1. For layers with an id property, use non-strict equality on it (e.g. '2' and 2 are equivalent);
2. For layers without id, compute a hash of their base properties excluding the extras property

Determining whether layers have changed is done like so:

1. For layers with an id property, the value of the version field is compared; if values are different (using non-strict equality), then the layer is considered to have changed; otherwise it is considered to have remained the same
2. For layers without id, a full hash is computed including the extras property; this means that a layer which only had changes in its extras object will not be considered added/removed, but only changed

Parameters

• nextContext: MapContext

• previousContext: MapContext

Returns

MapContextDiff

Defined in

packages/core/lib/utils/map-context-diff.ts:30