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// Encoding documentation: |
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// https://en.wikipedia.org/wiki/International_Article_Number_(EAN)#Binary_encoding_of_data_digits_into_EAN-13_barcode |
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import { SIDE_BIN, MIDDLE_BIN, EAN13_STRUCTURE } from './constants'; |
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import encode from './encoder'; |
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import Barcode from '../Barcode'; |
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// Calculate the checksum digit |
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// https://en.wikipedia.org/wiki/International_Article_Number_(EAN)#Calculation_of_checksum_digit |
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const checksum = (number) => { |
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const res = number |
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.substr(0, 12) |
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.split('') |
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.map((n) => +n) |
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.reduce((sum, a, idx) => { |
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return idx % 2 |
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? sum + a * 3 |
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: sum + a; |
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}, 0); |
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return (10 - (res % 10)) % 10; |
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}; |
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class EAN13 extends Barcode { |
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constructor(data, options) { |
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// Add checksum if it does not exist |
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if (data.search(/^[0-9]{12}$/) !== -1) { |
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data += checksum(data); |
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} |
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super(data, options); |
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// Make sure the font is not bigger than the space between the guard bars |
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this.fontSize = !options.flat && options.fontSize > options.width * 10 |
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? options.width * 10 |
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: options.fontSize; |
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// Make the guard bars go down half the way of the text |
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this.guardHeight = options.height + this.fontSize / 2 + options.textMargin; |
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// Adds a last character to the end of the barcode |
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this.lastChar = options.lastChar; |
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} |
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valid() { |
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return ( |
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this.data.search(/^[0-9]{13}$/) !== -1 && |
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+this.data[12] === checksum(this.data) |
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); |
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} |
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encode() { |
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return this.options.flat |
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? this.encodeFlat() |
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: this.encodeGuarded(); |
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} |
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get leftData() { |
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return this.data.substr(1, 6); |
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} |
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get rightData() { |
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return this.data.substr(7, 6); |
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} |
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// The "standard" way of printing EAN13 barcodes with guard bars |
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encodeGuarded() { |
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const textOptions = { fontSize: this.fontSize }; |
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const guardOptions = { height: this.guardHeight }; |
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const data = [ |
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{ |
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data: SIDE_BIN, |
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options: guardOptions |
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}, |
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{ |
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data: encode(this.leftData, EAN13_STRUCTURE[this.data[0]]), |
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text: this.text.substr(1, 6), |
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options: textOptions |
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}, |
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{ |
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data: MIDDLE_BIN, |
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options: guardOptions |
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}, |
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{ |
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data: encode(this.rightData, 'RRRRRR'), |
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text: this.text.substr(7, 6), |
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options: textOptions |
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}, |
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{ |
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data: SIDE_BIN, |
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options: guardOptions |
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}, |
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]; |
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if (this.options.displayValue) { |
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data.unshift({ |
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data: '000000000000', |
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text: this.text.substr(0, 1), |
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options: { textAlign: 'left', ...textOptions } |
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}); |
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if (this.options.lastChar) { |
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data.push({ |
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data: '00' |
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}); |
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data.push({ |
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data: '00000', |
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text: this.options.lastChar, |
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options: textOptions |
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}); |
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} |
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} |
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return data; |
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} |
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encodeFlat() { |
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const left = encode(this.leftData, EAN13_STRUCTURE[this.data[0]]); |
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const right = encode(this.rightData, 'RRRRRR'); |
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return { |
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data: [SIDE_BIN, left, MIDDLE_BIN, right, SIDE_BIN].join(''), |
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text: this.text |
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}; |
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} |
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} |
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export default EAN13; |
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