This site describes solve-engine as it is on main: 2.43.0, which npm does not have yet. npm installs 2.40.0, so a page may show an answer that version does not give yet.

combineSources

function combineSources(a, b):
  | readonly ValueSource[]
  | undefined;

Defined in: packages/engine/src/vm/Provenance.ts:97

The sources of a value computed from two others: every record either carries, each once, the left operand’s first.

Returns one of its arguments unchanged whenever it can (either side empty, or both the same list, or the right adding nothing new), so the common case of a sourced value meeting a plain number allocates nothing.

Parameters

Parameter	Type	Description
`a`	\| readonly `ValueSource`[] \| `undefined`	The left operand’s sources, if any.
`b`	\| readonly `ValueSource`[] \| `undefined`	The right operand’s sources, if any.

Returns

| readonly ValueSource[] | undefined

The merged list, or undefined when neither side has a source.