index.js

function checkOverflow() {
	const swiper = this;
	const {
		isLocked: wasLocked,
		params
	} = swiper;
	const {
		slidesOffsetBefore
	} = params;

	if (slidesOffsetBefore) {
		const lastSlideIndex = swiper.slides.length - 1;
		const lastSlideRightEdge = swiper.slidesGrid[lastSlideIndex] + swiper.slidesSizesGrid[lastSlideIndex] +
			slidesOffsetBefore * 2;
		swiper.isLocked = swiper.size > lastSlideRightEdge;
	} else {
		swiper.isLocked = swiper.snapGrid.length === 1;
	}

	if (params.allowSlideNext === true) {
		swiper.allowSlideNext = !swiper.isLocked;
	}

	if (params.allowSlidePrev === true) {
		swiper.allowSlidePrev = !swiper.isLocked;
	}

	if (wasLocked && wasLocked !== swiper.isLocked) {
		swiper.isEnd = false;
	}

	if (wasLocked !== swiper.isLocked) {
		swiper.emit(swiper.isLocked ? 'lock' : 'unlock');
	}
}

export default {
	checkOverflow
};