lindell / JsBarcode

import EAN from './EAN';

// Calculate the checksum digit

const checksum = (number) => {

	const res = number

		.substr(0, 7)

		.split('')

		.map((n) => +n)

		.reduce((sum, a, idx) => (

			idx % 2 ? sum + a : sum + a * 3

		), 0);

	return (10 - (res % 10)) % 10;

};

class EAN8 extends EAN {

	constructor(data, options) {

		// Add checksum if it does not exist

		if (data.search(/^[0-9]{7}$/) !== -1) {

			data += checksum(data);

		}

		super(data, options);

	}

	valid() {

		return (

			this.data.search(/^[0-9]{8}$/) !== -1 &&

			+this.data[7] === checksum(this.data)

		);

	}

	leftText() {

		return super.leftText(0, 4);

	}

	leftEncode() {

		const data = this.data.substr(0, 4);

		return super.leftEncode(data, 'LLLL');

	}

	rightText() {

		return super.rightText(4, 4);

	}

	rightEncode() {

		const data = this.data.substr(4, 4);

		return super.rightEncode(data, 'RRRR');

	}

}

export default EAN8;