前端工具函数封装---持续更新

文件下载

export class DownloadRobot {
  stream;
  constructor() {}
  pick(stream) {
    this.stream = stream;
    return this;
  }
  put(name) {
    var blob = new Blob([this.stream.data], {
      type: this.stream.type,
    });
    var link = document.createElement('a');
    link.href = window.URL.createObjectURL(blob);
    link.download = name || '';
    link.click();
    window.URL.revokeObjectURL(link.href);
  }
  downUrl(fileName, url) {
    let a = document.createElement('a');
    a.href = url;
    a.download = fileName;
    a.click();
    a.remove();
  }
  fileRead(text) {
    return new Promise((resolve) => {
      const reader = new FileReader();
      reader.onload = () => {
        const { result } = reader;
        resolve(JSON.parse(result));
      };
      reader.readAsText(text);
    });
  }
}

使用

      //  方式一：
	const downloadRobot = new DownloadRobot()
	downloadRobot.pick(res)
	downloadRobot.put(fileList[0].name)
      //  方式二：
        downloadRobot.downUrl(item.fileName, item.fileUrl)

获取URL参数

/**
 * @param {string} url
 * @returns {Object}
 */
export function getQueryObject(url) {
  url = url == null ? window.location.href : url
  const search = url.substring(url.lastIndexOf('?') + 1)
  const obj = {}
  const reg = /([^?&=]+)=([^?&=]*)/g
  search.replace(reg, (rs, $1, $2) => {
    const name = decodeURIComponent($1)
    let val = decodeURIComponent($2)
    val = String(val)
    obj[name] = val
    return rs
  })
  return obj
}

获取字节长度

export function byteLength(str) {
  // returns the byte length of an utf8 string
  let s = str.length
  for (var i = str.length - 1; i >= 0; i--) {
    const code = str.charCodeAt(i)
    if (code > 0x7f && code <= 0x7ff) s++
    else if (code > 0x7ff && code <= 0xffff) s += 2
    if (code >= 0xdc00 && code <= 0xdfff) i--
  }
  return s
}

是不是数字字符串

export function isNumberStr(str) {
  return /^[+-]?(0|([1-9]\d*))(\.\d+)?$/g.test(str)
}

下划转驼峰

export function camelCase(str) {
  return str.replace(/_[a-z]/g, (str1) => str1.substr(-1).toUpperCase())
}

首字母大小

export function titleCase(str) {
  return str.replace(/( |^)[a-z]/g, (L) => L.toUpperCase())
}

验证是否为blob格式

export async function blobValidate(data) {
  try {
    const text = await data.text();
    JSON.parse(text);
    return false;
  } catch (error) {
    return true;
  }
}

构造树型结构数据

/**
 * 构造树型结构数据
 * @param {*} data 数据源
 * @param {*} id id字段 默认 'id'
 * @param {*} parentId 父节点字段 默认 'parentId'
 * @param {*} children 孩子节点字段 默认 'children'
 */
export function handleTree(data, id, parentId, children) {
  let config = {
    id: id || 'id',
    parentId: parentId || 'parentId',
    childrenList: children || 'children'
  };

  var childrenListMap = {};
  var nodeIds = {};
  var tree = [];

  for (let d of data) {
    let parentId = d[config.parentId];
    if (childrenListMap[parentId] == null) {
      childrenListMap[parentId] = [];
    }
    nodeIds[d[config.id]] = d;
    childrenListMap[parentId].push(d);
  }

  for (let d of data) {
    let parentId = d[config.parentId];
    if (nodeIds[parentId] == null) {
      tree.push(d);
    }
  }

  for (let t of tree) {
    adaptToChildrenList(t);
  }

  function adaptToChildrenList(o) {
    if (childrenListMap[o[config.id]] !== null) {
      o[config.childrenList] = childrenListMap[o[config.id]];
    }
    if (o[config.childrenList]) {
      for (let c of o[config.childrenList]) {
        adaptToChildrenList(c);
      }
    }
  }
  return tree;
}