dnd-core/src/utils/equality.ts

Drag and drop sans the GUI

import { XYCoord } from '../interfaces'

export type EqualityCheck<T> = (a: T, b: T) => boolean
export const strictEquality = <T>(a: T, b: T) => a === b

/**
 * Determine if two cartesian coordinate offsets are equal
 * @param offsetA
 * @param offsetB
 */
export function areCoordsEqual(
	offsetA: XYCoord | null | undefined,
	offsetB: XYCoord | null | undefined,
) {
	if (!offsetA && !offsetB) {
		return true
	} else if (!offsetA || !offsetB) {
		return false
	} else {
		return offsetA.x === offsetB.x && offsetA.y === offsetB.y
	}
}

/**
 * Determines if two arrays of items are equal
 * @param a The first array of items
 * @param b The second array of items
 */
export function areArraysEqual<T>(
	a: T[],
	b: T[],
	isEqual: EqualityCheck<T> = strictEquality,
) {
	if (a.length !== b.length) {
		return false
	}
	for (let i = 0; i < a.length; ++i) {
		if (!isEqual(a[i], b[i])) {
			return false
		}
	}
	return true
}