关于导出数据到Excel的方式，简单搜了下掘金，后端前端八仙过海。
我是个菜鸡，不太清楚导出的各种方式，el-admin的纯前端导出很简单，在此做个记录。
第一步
肯定就是环境啦！官方说Export2Excel不仅依赖js-xlsx还依赖file-saver和script-loader。
但是我在我手上的这个项目里面是没有看见js-xlsx的，
但是我看见了xlsx，并且在ExportExcel文件中引入，而且官方自己还装的xlsx。
//官方给出的。 js-xlsx我不太清楚在哪
npm install xlsx file-saver -S
npm install script-loader -S -D
第二步
需要两个文件，一个Blob.js，一个导出文件(ExportExcel.js)，这两文件会在底部给出，免得占位置。
第三步就是怎么用了
//现在还差一个函数 此函数将对象数组转为需要的二维数组（Excel表本来就是个二维矩阵）
function formatJson (filterVal, jsonData) {
return jsonData.map(v => filterVal.map(j => v[j]))
}
//小Demo
//webpack引入文件的方式，返回一个promise，vendor是该文件放置的位置(各位看官水平难免参差不齐，大佬多担待)
import('vendor/ExportExcel').then(({ export_json_to_excel }) => {
//表头
const tHeader = ['月份','到期人数','复购人数','复购占比','流失人数','流失占比','免费人数','免费占比']
//表头对应的字段
const filterVal = ['statMonth','expireCount','repurchaseCount','repurchaseRate',
'lossCount','lossRate','freeCount','freeRate']
//导出的数据需要是二维数组的形式，这里将params转为需要的数据结构
const data = formatJson(filterVal, params)
let excelName = `到期用户转化情况`;
export_json_to_excel(tHeader, data, excelName)
})
//export_json_to_excel导出函数第一个参数为表头 第二个为表数据 第三个为文件名
//excel表中的数据表现形式必须为一个二维数组也就是二维矩阵
//自己要处理好二维矩阵的排列
//还不清楚导出所需要的数据构成的同学
//a为需要导出的这个数据结构，formatJson可以帮你转化一手
var a = [{ expireCount: 1596, freeCount: 0, freeRate: "0%", lossCount: 1596, lossRate: "100%", repurchaseCount: 0, repurchaseRate: "0%", statMonth: "2020-09"}]
const filterVal = [ 'statMonth', 'expireCount', 'repurchaseCount', 'repurchaseRate', 'lossCount', 'lossRate', 'freeCount', 'freeRate']
const data = formatJson(filterVal, a)
//data: [ [ '2020-09', 1596, 0, '0%', 1596, '100%', 0, '0%' ] ]
//故此可见 能导出excel的数据格式为一个数组，数组中的项也为数组
如果数据处理得不对，可能会卡死浏览器，可能会没有任何反应，有兴趣的同学可以记一笔，这种又简单、纯前端。
两个文件源码，复制粘贴，放好位置，反正我是看不太懂这两文件的
Blob.js
/* eslint-disable */
(function (view) {
"use strict";
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 BlobBuilder
var BlobBuilder = view.BlobBuilder || view.WebKitBlobBuilder || view.MozBlobBuilder || (function(view) {
var
get_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) {
var
type = 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 string
if (Uint8Array && (data instanceof ArrayBuffer || data instanceof Uint8Array)) {
var
str = ""
, 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 sync
throw 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 string
bb.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));
ExportExcel.js 看官注意一下，这里引入了Blob的，注意一下引入的位置
/* eslint-disable */
import 'file-saver'
import 'vendor/Blob'
import XLSX from 'xlsx'
function generateArray(table) {
var out = [];
var rows = table.querySelectorAll('tr');
var ranges = [];
for (var R = 0; R < rows.length; ++R) {
var outRow = [];
var row = rows[R];
var columns = row.querySelectorAll('td');
for (var C = 0; C < columns.length; ++C) {
var cell = columns[C];
var colspan = cell.getAttribute('colspan');
var rowspan = cell.getAttribute('rowspan');
var cellValue = cell.innerText;
if (cellValue !== "" && cellValue == +cellValue) cellValue = +cellValue;
//Skip ranges
ranges.forEach(function (range) {
if (R >= range.s.r && R <= range.e.r && outRow.length >= range.s.c && outRow.length <= range.e.c) {
for (var i = 0; i <= range.e.c - range.s.c; ++i) outRow.push(null);
}
});
//Handle Row Span
if (rowspan || colspan) {
rowspan = rowspan || 1;
colspan = colspan || 1;
ranges.push({s: {r: R, c: outRow.length}, e: {r: R + rowspan - 1, c: outRow.length + colspan - 1}});
}
;
//Handle Value
outRow.push(cellValue !== "" ? cellValue : null);
//Handle Colspan
if (colspan) for (var k = 0; k < colspan - 1; ++k) outRow.push(null);
}
out.push(outRow);
}
return [out, ranges];
};
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;
}
export function export_table_to_excel(id) {
var theTable = document.getElementById(id);
var oo = generateArray(theTable);
var ranges = oo[1];
/* original data */
var data = oo[0];
var ws_name = "SheetJS";
var wb = new Workbook(), ws = sheet_from_array_of_arrays(data);
/* add ranges to worksheet */
// ws['!cols'] = ['apple', 'banan'];
ws['!merges'] = ranges;
/* add worksheet to workbook */
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"}), "test.xlsx")
}
export function export_json_to_excel(th, jsonData, defaultTitle) {
/* original data */
var data = jsonData;
data.unshift(th);
var ws_name = "SheetJS";
var wb = new Workbook(), ws = sheet_from_array_of_arrays(data);
/*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) {
return {'wch': 10};
}
/*再判断是否为中文*/
else if (val.toString().charCodeAt(0) > 255) {
return {'wch': val.toString().length * 2};
} else {
return {'wch': val.toString().length};
}
}))
/*以第一行为初始值*/
let result = colWidth[0];
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;
/* add worksheet to workbook */
wb.SheetNames.push(ws_name);
wb.Sheets[ws_name] = ws;
var wbout = XLSX.write(wb, {bookType: 'xlsx', bookSST: false, type: 'binary'});
var title = defaultTitle || 'excel-list'
saveAs(new Blob([s2ab(wbout)], {type: "application/octet-stream"}), title + ".xlsx")
}
这个文件在底部抛出了两个函数
export_json_to_excel（这个就是我们需要的）
和
export_table_to_excel（这个没用过不知道）
