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// 打印机纸宽58mm，页的宽度384，字符宽度为1，每行最多盛放32个字符
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const PAGE_WIDTH = 384;
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const MAX_CHAR_COUNT_EACH_LINE = 32;
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/**
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* @param str
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* @returns {boolean} str是否全是中文
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*/
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function isChinese(str) {
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return /^[\u4e00-\u9fa5]$/.test(str);
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}
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/**
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* 返回字符串宽度(1个中文=2个英文字符)
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* @param str
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* @returns {number}
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*/
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function getStringWidth(str) {
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let width = 0;
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for (let i = 0, len = str.length; i < len; i++) {
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width += isChinese(str.charAt(i)) ? 2 : 1;
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}
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return width;
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}
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/**
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* 同一行输出str1, str2，str1居左, str2居右
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* @param {string} str1 内容1
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* @param {string} str2 内容2
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* @param {number} fontWidth 字符宽度 1/2
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* @param {string} fillWith str1 str2之间的填充字符
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*
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*/
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function inline(str1, str2, fillWith = ' ', fontWidth = 1) {
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const lineWidth = MAX_CHAR_COUNT_EACH_LINE / fontWidth;
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// 需要填充的字符数量
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let fillCount = lineWidth - (getStringWidth(str1) + getStringWidth(str2)) % lineWidth;
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let fillStr = new Array(fillCount).fill(fillWith.charAt(0)).join('');
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return str1 + fillStr + str2;
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}
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/**
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* 用字符填充一整行
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* @param {string} fillWith 填充字符
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* @param {number} fontWidth 字符宽度 1/2
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*/
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function fillLine(fillWith = '-', fontWidth = 1) {
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const lineWidth = MAX_CHAR_COUNT_EACH_LINE / fontWidth;
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return new Array(lineWidth).fill(fillWith.charAt(0)).join('');
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}
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/**
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* 文字内容居中，左右用字符填充
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* @param {string} str 文字内容
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* @param {number} fontWidth 字符宽度 1/2
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* @param {string} fillWith str1 str2之间的填充字符
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*/
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function fillAround(str, fillWith = '-', fontWidth = 1) {
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const lineWidth = MAX_CHAR_COUNT_EACH_LINE / fontWidth;
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let strWidth = getStringWidth(str);
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// 内容已经超过一行了，没必要填充
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if (strWidth >= lineWidth) {
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return str;
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}
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// 需要填充的字符数量
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let fillCount = lineWidth - strWidth;
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// 左侧填充的字符数量
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let leftCount = Math.round(fillCount / 2);
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// 两侧的填充字符，需要考虑左边需要填充，右边不需要填充的情况
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let fillStr = new Array(leftCount).fill(fillWith.charAt(0)).join('');
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return fillStr + str + fillStr.substr(0, fillCount - leftCount);
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}
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// ArrayBuffer转16进度字符串示例
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function ab2hex(buffer) {
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const hexArr = Array.prototype.map.call(
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new Uint8Array(buffer),
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function(bit) {
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return ('00' + bit.toString(16)).slice(-2)
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}
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)
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return hexArr.join(',')
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}
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module.exports = {
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inline: inline,
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fillLine: fillLine,
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fillAround: fillAround,
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ab2hex:ab2hex,
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};
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