Method getConstituentTypeForKeyType

internal/checker/relater.go:1131–1137

Given a union type for which getKeyPropertyName returned a non-empty string, return the constituent that corresponds to the given key type for that property name.

(t *Type, keyType *Type)

// Given a union type for which getKeyPropertyName returned a non-empty string, return the constituent
// that corresponds to the given key type for that property name.
func (c *Checker) getConstituentTypeForKeyType(t *Type, keyType *Type) *Type {
	result := t.AsUnionType().constituentMap[c.getRegularTypeOfLiteralType(keyType)]
	if result != c.unknownType {
		return result
	}
	return nil
}

func (c *Checker) computeKeyPropertyNameAndMap(t *Type) (string, map[*Type]*Type) {
	types := t.Types()