vue blob实现自定义多sheet数据导出到excel文件

背景：最近vue项目遇到一个需求，就是需要将多个表格分成不同sheet页并导出，之前的工具类只能导出一个sheet页，所以在原有的基础上，调整一下，让它支持多sheet导出。

1. vue blob文件流，这个肯定要的，这个百度一下都有，下面贴出来

(function (view) {view.URL = view.URL || view.webkitURL;if (view.Blob && view.URL) {try {new Blob;return;} catch (e) {}}// Internally we use a BlobBuilder implementation to base Blob off of// in order to support older browsers that only have BlobBuildervar BlobBuilder = view.BlobBuilder || view.WebKitBlobBuilder || view.MozBlobBuilder || (function(view) {varget_class = function(object) {return Object.prototype.toString.call(object).match(/^\[object\s(.*)\]$/)[1];}, FakeBlobBuilder = function BlobBuilder() {this.data = [];}, FakeBlob = function Blob(data, type, encoding) {this.data = data;this.size = data.length;this.type = type;this.encoding = encoding;}, FBB_proto = FakeBlobBuilder.prototype, FB_proto = FakeBlob.prototype, FileReaderSync = view.FileReaderSync, FileException = function(type) {this.code = this[this.name = type];}, file_ex_codes = ("NOT_FOUND_ERR SECURITY_ERR ABORT_ERR NOT_READABLE_ERR ENCODING_ERR "+ "NO_MODIFICATION_ALLOWED_ERR INVALID_STATE_ERR SYNTAX_ERR").split(" "), file_ex_code = file_ex_codes.length, real_URL = view.URL || view.webkitURL || view, real_create_object_URL = real_URL.createObjectURL, real_revoke_object_URL = real_URL.revokeObjectURL, URL = real_URL, btoa = view.btoa, atob = view.atob, ArrayBuffer = view.ArrayBuffer, Uint8Array = view.Uint8Array;FakeBlob.fake = FB_proto.fake = true;while (file_ex_code--) {FileException.prototype[file_ex_codes[file_ex_code]] = file_ex_code + 1;}if (!real_URL.createObjectURL) {URL = view.URL = {};}URL.createObjectURL = function(blob) {vartype = blob.type, data_URI_header;if (type === null) {type = "application/octet-stream";}if (blob instanceof FakeBlob) {data_URI_header = "data:" + type;if (blob.encoding === "base64") {return data_URI_header + ";base64," + blob.data;} else if (blob.encoding === "URI") {return data_URI_header + "," + decodeURIComponent(blob.data);} if (btoa) {return data_URI_header + ";base64," + btoa(blob.data);} else {return data_URI_header + "," + encodeURIComponent(blob.data);}} else if (real_create_object_URL) {return real_create_object_URL.call(real_URL, blob);}};URL.revokeObjectURL = function(object_URL) {if (object_URL.substring(0, 5) !== "data:" && real_revoke_object_URL) {real_revoke_object_URL.call(real_URL, object_URL);}};FBB_proto.append = function(data/*, endings*/) {var bb = this.data;// decode data to a binary stringif (Uint8Array && (data instanceof ArrayBuffer || data instanceof Uint8Array)) {varstr = "", buf = new Uint8Array(data), i = 0, buf_len = buf.length;for (; i < buf_len; i++) {str += String.fromCharCode(buf[i]);}bb.push(str);} else if (get_class(data) === "Blob" || get_class(data) === "File") {if (FileReaderSync) {var fr = new FileReaderSync;bb.push(fr.readAsBinaryString(data));} else {// async FileReader won't work as BlobBuilder is syncthrow new FileException("NOT_READABLE_ERR");}} else if (data instanceof FakeBlob) {if (data.encoding === "base64" && atob) {bb.push(atob(data.data));} else if (data.encoding === "URI") {bb.push(decodeURIComponent(data.data));} else if (data.encoding === "raw") {bb.push(data.data);}} else {if (typeof data !== "string") {data += ""; // convert unsupported types to strings}// decode UTF-16 to binary stringbb.push(unescape(encodeURIComponent(data)));}};FBB_proto.getBlob = function(type) {if (!arguments.length) {type = null;}return new FakeBlob(this.data.join(""), type, "raw");};FBB_proto.toString = function() {return "[object BlobBuilder]";};FB_proto.slice = function(start, end, type) {var args = arguments.length;if (args < 3) {type = null;}return new FakeBlob(this.data.slice(start, args > 1 ? end : this.data.length), type, this.encoding);};FB_proto.toString = function() {return "[object Blob]";};FB_proto.close = function() {this.size = this.data.length = 0;};return FakeBlobBuilder;}(view));view.Blob = function Blob(blobParts, options) {var type = options ? (options.type || "") : "";var builder = new BlobBuilder();if (blobParts) {for (var i = 0, len = blobParts.length; i < len; i++) {builder.append(blobParts[i]);}}return builder.getBlob(type);};
}(typeof self !== "undefined" && self || typeof window !== "undefined" && window || this.content || this));

2. Ex2ExcelUtils.js，导出工具类

require('script-loader!file-saver');
require('./Blob');
require('script-loader!xlsx/dist/xlsx.core.min');/*** 支持多sheet* @param sheetNames* @param ths 表头* @param jsonDatas 数据* @param defaultTitle*/
export function export_data_to_excel(sheetNames, ths, jsonDatas, defaultTitle) {var wb = new Workbook()for(let index in sheetNames){let th = ths[index]var data = deepCopy(jsonDatas[index]);data.unshift(th);var ws_name = sheetNames[index];var ws = sheet_from_array_of_arrays(data);//================表格宽度自适应====================/*设置worksheet每列的最大宽度*/const colWidth = data.map(row =>row.map(val => {/*先判断是否为null/undefined*/if (val == null || val == undefined || val == "") {return {wch: 10};} else if (val.toString().charCodeAt(0) > 255) {/*再判断是否为中文*/return {wch: val.toString().length * 2};} else {return {wch: val.toString().length * 1.4};}}));/*以主表第二行为初始值，因为我的第一行是表格标题，会比较长，所以以主表第二行为初始值*/let result = colWidth[1];for (let i = 1; i < colWidth.length; i++) {for (let j = 0; j < colWidth[i].length; j++) {if (result[j]["wch"] < colWidth[i][j]["wch"]) {result[j]["wch"] = colWidth[i][j]["wch"];}}}ws["!cols"] = result;//====================表格宽度自适应-结束=================wb.SheetNames.push(ws_name);wb.Sheets[ws_name] = ws;}var wbout = XLSX.write(wb, {bookType: 'xlsx', bookSST: false, type: 'binary'});saveAs(new Blob([s2ab(wbout)], {type: "application/octet-stream"}), defaultTitle + ".xlsx")
}function datenum(v, date1904) {if (date1904) v += 1462;var epoch = Date.parse(v);return (epoch - new Date(Date.UTC(1899, 11, 30))) / (24 * 60 * 60 * 1000);
}function sheet_from_array_of_arrays(data, opts) {var ws = {};var range = {s: {c: 10000000, r: 10000000}, e: {c: 0, r: 0}};for (var R = 0; R != data.length; ++R) {for (var C = 0; C != data[R].length; ++C) {if (range.s.r > R) range.s.r = R;if (range.s.c > C) range.s.c = C;if (range.e.r < R) range.e.r = R;if (range.e.c < C) range.e.c = C;var cell = {v: data[R][C]};if (cell.v == null) continue;var cell_ref = XLSX.utils.encode_cell({c: C, r: R});if (typeof cell.v === 'number') cell.t = 'n';else if (typeof cell.v === 'boolean') cell.t = 'b';else if (cell.v instanceof Date) {cell.t = 'n';cell.z = XLSX.SSF._table[14];cell.v = datenum(cell.v);}else cell.t = 's';ws[cell_ref] = cell;}}if (range.s.c < 10000000) ws['!ref'] = XLSX.utils.encode_range(range);return ws;
}function Workbook() {if (!(this instanceof Workbook)) return new Workbook();this.SheetNames = [];this.Sheets = {};
}function s2ab(s) {var buf = new ArrayBuffer(s.length);var view = new Uint8Array(buf);for (var i = 0; i != s.length; ++i) view[i] = s.charCodeAt(i) & 0xFF;return buf;
}

3. 上述两个文件，放在同一个目录下，以下是调用示例

// 文件名
const excelName = '多sheet页数据导出'
// 声名每个sheet页的名称
let sheetNames = ['sheet1', 'sheet2', 'sheet3']
// 每个sheet页的表头
let ths = [[], [], []]
// 每个sheet页的数据内容
let jsonDatas = [[], [], []]// sheet1
ths[0] = ['表头A1', '表头A2', '表头A3', '表头A4']
jsonDatas[0] = [['值A1', '值A2', '值A3', '值A4'],['值B1', '值B2', '值B3', '值B4']]
// sheet2
ths[1] = ['表头A11', '表头A21', '表头A31', '表头A41']
jsonDatas[1] = [['值A11', '值A21', '值A31', '值A41'],['值B11', '值B21', '值B31', '值B41']]
// sheet3
ths[2] = ['表头A12', '表头A22', '表头A32', '表头A42']
jsonDatas[2] = [['值A12', '值A22', '值A32', '值A42'],['值B12', '值B22', '值B32', '值B42']]const { export_data_to_excel} = require('./Ex2ExcelUtils')
export_data_to_excel(sheetNames, ths, jsonDatas, excelName)

最后：前端或后端导出文件，可以看自己需求。数据量比较少的时候，或页面展示的是所有数据的时候，使用前端js直接导出文件，比较方便，因为不用重查接口，减少了交互。若数据量比较大，或页面展示的是分页时，推荐走后端接口导出文件，因为没法拿到完整的数据，而且大数据量从接口返回到前端，对前端负担也不友好。