工具类js聚合

数据前端存数据的下载功能

function downloadExl(data, type) {
	var keys = Object.keys(data[0])
	var firstRow = {}
	keys.forEach(function(item) {
		firstRow[item] = item
	})
	data.unshift(firstRow)

	var content = {}

把json格式的数据转为excel的行列形式

	var sheetsData = data
		.map(function(item, rowIndex) {
			return keys.map(function(key, columnIndex) {
				return Object.assign(
					{},
					{
						value: item[key],
						position:
							(columnIndex > 25
								? getCharCol(columnIndex)
								: String.fromCharCode(65 + columnIndex)) +
							(rowIndex + 1),
					}
				)
			})
		})
		.reduce(function(prev, next) {
			return prev.concat(next)
		})

	sheetsData.forEach(function(item) {
		content[item.position] = { v: item.value }
	})

设置区域,比如表格从A1到D10,SheetNames:标题，

	var coordinate = Object.keys(content)
	var workBook = {
		SheetNames: ['helloSheet'],
		Sheets: {
			helloSheet: Object.assign({}, content, {
				'!ref': coordinate[0] + ':' + coordinate[coordinate.length - 1],
			}),
		},
	}
	//这里的数据是用来定义导出的格式类型
	var excelData = XLSX.write(workBook, {
		bookType: 'xlsx',
		bookSST: false,
		type: 'binary',
	})
	var blob = new Blob([string2ArrayBuffer(excelData)], { type: '' })
	FileSaver.saveAs(blob, 'hello.xlsx')
}

字符串转字符流

function string2ArrayBuffer(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
}

将指定的自然数转换为26进制表示。映射关系：[0-25] -> [A-Z]。

function getCharCol(n) {
	let s = '',
		m = 0
	while (n > 0) {
		m = (n % 26) + 1
		s = String.fromCharCode(m + 64) + s
		n = (n - m) / 26
	}
	return s
}