mirror of https://github.com/espruino/BangleApps
58 lines
1.0 KiB
JavaScript
58 lines
1.0 KiB
JavaScript
// Encoding documentation:
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// http://www.barcodeisland.com/ean8.phtml
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const EAN = require("cards.EAN.js");
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// Calculate the checksum digit
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const checksum = (number) => {
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const res = number
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.substr(0, 7)
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.split('')
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.map((n) => +n)
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.reduce((sum, a, idx) => (
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idx % 2 ? sum + a : sum + a * 3
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), 0);
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return (10 - (res % 10)) % 10;
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};
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class EAN8 extends EAN {
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constructor(data, options) {
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// Add checksum if it does not exist
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if (/^[0-9][0-9][0-9][0-9][0-9][0-9][0-9]$/.test(data)) {
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data += checksum(data);
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}
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super(data, options);
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}
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valid() {
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return (
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/^[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]$/.test(this.data) &&
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+this.data[7] === checksum(this.data)
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);
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}
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leftText() {
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return super.leftText(0, 4);
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}
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leftEncode() {
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const data = this.data.substr(0, 4);
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return super.leftEncode(data, 'LLLL');
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}
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rightText() {
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return super.rightText(4, 4);
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}
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rightEncode() {
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const data = this.data.substr(4, 4);
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return super.rightEncode(data, 'RRRR');
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}
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}
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module.exports = EAN8;
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