csv encode and export

encode-csv.js

/**
 * csv data encode
 * var data = [[1850, 20, 0, 1, 1017281], [1850, 20, 0, 2, 1003841]];
 * encode(data)
 * encode(data,{ header: ["year", "age", "status", "sex", "population"] })
 * encode([{age:xx,name:'xxx'}], {header:true})
 * options:{ delimiter:'分隔符',newline:换行符,skip:头部跳过数量，header:Object或者arrat }
 */

const CELL_DELIMITERS = [',', ';', '\t', '|', '^']
const LINE_DELIMITERS = ['\r\n', '\r', '\n']

const STANDARD_ENCODE_OPTS = {
  delimiter: CELL_DELIMITERS[0],
  newline: LINE_DELIMITERS[0],
  skip: 0,
  limit: false,
  header: false
}

const quoteMark = '"'
const doubleQuoteMark = '""'
const quoteRegex = /"/g

const getType = (obj) => Object.prototype.toString.call(obj).slice(8, -1)

const getLimit = (limit, len) => limit === false ? len : limit

function encodeCells (line, delimiter, newline) {
  let row = line.slice(0)
  for (let i = 0, len = row.length; i < len; i++) {
    if (typeof row[i] !== 'string') {
      continue
    }
    if (row[i].indexOf(quoteMark) !== -1) {
      row[i] = row[i].replace(quoteRegex, doubleQuoteMark)
    }
    if (row[i].indexOf(delimiter) !== -1 || row[i].indexOf(newline) !== -1) {
      row[i] = quoteMark + row[i] + quoteMark
    }
  }
  return row.join(delimiter)
}

function encodeArrays (coll, opts, fn) {
  let delimiter = opts.delimiter
  let newline = opts.newline

  if (opts.header && getType(opts.header) === 'Array') {
    fn(encodeCells(opts.header, delimiter, newline))
  }

  for (let cur = 0, lim = getLimit(opts.limit, coll.length); cur < lim; cur++) {
    fn(encodeCells(coll[cur], delimiter, newline))
  }

  return true
}

function encodeObjects (coll, opts, fn) {
  let delimiter = opts.delimiter
  let newline = opts.newline
  let header
  let row

  header = []
  row = []
  for (let key in coll[0]) {
    header.push(key)
    row.push(coll[0][key])
  }

  if (opts.header === true) {
    fn(encodeCells(header, delimiter, newline))
  } else if (getType(opts.header) === 'Array') {
    fn(encodeCells(opts.header, delimiter, newline))
  }

  fn(encodeCells(row, delimiter))

  for (let cur = 1, lim = getLimit(opts.limit, coll.length); cur < lim; cur++) {
    row = []
    for (let key = 0, len = header.length; key < len; key++) {
      row.push(coll[cur][header[key]])
    }
    fn(encodeCells(row, delimiter, newline))
  }

  return true
}

export function encodeCsv (coll, opts, fn) {
  let lines

  if (getType(opts) === 'Function') {
    fn = opts
    opts = {}
  } else if (getType(fn) !== 'Function') {
    lines = []
    fn = lines.push.bind(lines)
  }

  opts = Object.assign({}, STANDARD_ENCODE_OPTS, opts)

  if (opts.skip > 0) {
    coll = coll.slice(opts.skip)
  }

  return (getType(coll[0]) === 'Array' ? encodeArrays : encodeObjects)(coll, opts, fn) &&
    (lines.length > 0 ? lines.join(opts.newline) : true)
}

export-csv.js

export function downloadCsv (csvFile, filename) {
  filename = `${filename}.csv`
  let blob = new Blob([csvFile], { type: 'text/csv;charset=utf-8;' })
  if (navigator.msSaveBlob) { // IE 10+
    navigator.msSaveBlob(blob, filename)
  } else {
    let link = document.createElement('a')
    if (link.download !== undefined) { // feature detection
        // Browsers that support HTML5 download attribute
      var url = URL.createObjectURL(blob)
      link.setAttribute('href', url)
      link.setAttribute('download', filename)
      link.style.visibility = 'hidden'
      document.body.appendChild(link)
      link.click()
      document.body.removeChild(link)
    }
  }
}