FVariantOperation<K extends FVariantConstraint, E extends FVariant, V, D extends Delta>.exact constructor

FVariantOperation<K extends FVariantConstraint, E extends FVariant, V, D extends Delta>.exact(Set<K> constraints, D delta)

Applies delta to the base and associates the result with each constraint in constraints.

Unlike FVariantOperation.match, this creates exact entries rather than matching existing variants.

// Given base: 0, {a: 1, b: 1}
.exact({b, c}, AddDelta(2)) // {a: 1, b: 3, c: 2}

See also:

• FVariantOperation.match for applying to variants whose constraint's variants are all present.
• FVariantOperation.base for applying to the base.
• FVariantOperation.variants for applying to all variants.
• FVariantOperation.all for applying to all variants and base.

Implementation

FVariantOperation.exact(Set<K> constraints, D delta)
  : _call = ((base, existing) => .raw(base, {
      ...existing,
      for (final constraint in constraints) constraint: delta(existing[constraint] ?? base) as V,
    }));