Function flatMorph

ark/util/flatMorph.ts:79–109

(
	o: object,
	flatMapEntry: (...args: any[]) => listable<GroupableEntry>
)

}

export const flatMorph: FlatMorph = (
	o: object,
	flatMapEntry: (...args: any[]) => listable<GroupableEntry>
): any => {
	const result: any = {}
	const inputIsArray = Array.isArray(o)
	let outputShouldBeArray = false

	for (const [i, entry] of Object.entries(o).entries()) {
		const mapped =
			inputIsArray ? flatMapEntry(i, entry[1]) : flatMapEntry(...entry, i)

		outputShouldBeArray ||= typeof mapped[0] === "number"

		const flattenedEntries =
			Array.isArray(mapped[0]) || mapped.length === 0 ?
				// if we have an empty array (for filtering) or an array with
				// another array as its first element, treat it as a list
				(mapped as GroupableEntry[])
				// otherwise, it should be a single entry, so nest it in a tuple
				// so it doesn't get spread when the result is flattened
			:	[mapped as GroupableEntry]

		for (const [k, v] of flattenedEntries) {
			if (typeof k === "object") result[k.group] = append(result[k.group], v)
			else result[k] = v
		}
	}

	return outputShouldBeArray ? Object.values(result) : result
}