你一定用得到的JS常用工具函数

时间格式化

/**
 * Parse the time to string
 * @param {(Object|string|number)} time
 * @param {string} cFormat
 * @returns {string | null}
 */
export function parseTime(time, cFormat) {
  if (arguments.length === 0) {
    return null;
  }
  const format = cFormat || "{y}-{m}-{d} {h}:{i}:{s}";
  let date;
  if (typeof time === "object") {
    date = time;
  } else {
    if (typeof time === "string" && /^[0-9]+$/.test(time)) {
      time = parseInt(time);
    }
    if (typeof time === "number" && time.toString().length === 10) {
      time = time * 1000;
    }
    date = new Date(time);
  }
  const formatObj = {
    y: date.getFullYear(),
    m: date.getMonth() + 1,
    d: date.getDate(),
    h: date.getHours(),
    i: date.getMinutes(),
    s: date.getSeconds(),
    a: date.getDay()
  };
  const time_str = format.replace(/{([ymdhisa])+}/g, (result, key) => {
    const value = formatObj[key];
    // Note: getDay() returns 0 on Sunday
    if (key === "a") {
      return ["日", "一", "二", "三", "四", "五", "六"][value];
    }
    return value.toString().padStart(2, "0");
  });
  return time_str;
}

时间转换

/**
 * @param {number} time
 * @param {string} option
 * @returns {string}
 */
export function formatTime(time, option) {
  if (("" + time).length === 10) {
    time = parseInt(time) * 1000;
  } else {
    time = +time;
  }
  const d = new Date(time);
  const now = Date.now();

  const diff = (now - d) / 1000;

  if (diff < 30) {
    return "刚刚";
  } else if (diff < 3600) {
    // less 1 hour
    return Math.ceil(diff / 60) + "分钟前";
  } else if (diff < 3600 * 24) {
    return Math.ceil(diff / 3600) + "小时前";
  } else if (diff < 3600 * 24 * 2) {
    return "1天前";
  }
  if (option) {
    return parseTime(time, option);
  } else {
    return (
      d.getMonth() +
      1 +
      "月" +
      d.getDate() +
      "日" +
      d.getHours() +
      "时" +
      d.getMinutes() +
      "分"
    );
  }
}

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;
}

获取字符串长度

/**
 * @param {string} input value
 * @returns {number} output value
 */
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;
}

合并对象

/**
 * Merges two objects, giving the last one precedence
 * @param {Object} target
 * @param {(Object|Array)} source
 * @returns {Object}
 */
export function objectMerge(target, source) {
  if (typeof target !== "object") {
    target = {};
  }
  if (Array.isArray(source)) {
    return source.slice();
  }
  Object.keys(source).forEach(property => {
    const sourceProperty = source[property];
    if (typeof sourceProperty === "object") {
      target[property] = objectMerge(target[property], sourceProperty);
    } else {
      target[property] = sourceProperty;
    }
  });
  return target;
}

函数防抖

/**
 * @param {Function} func
 * @param {number} wait
 * @param {boolean} immediate
 * @return {*}
 */
export function debounce(func, wait, immediate) {
  let timeout, args, context, timestamp, result;

  const later = function() {
    // 据上一次触发时间间隔
    const last = +new Date() - timestamp;

    // 上次被包装函数被调用时间间隔 last 小于设定时间间隔 wait
    if (last < wait && last > 0) {
      timeout = setTimeout(later, wait - last);
    } else {
      timeout = null;
      // 如果设定为immediate===true，因为开始边界已经调用过了此处无需调用
      if (!immediate) {
        result = func.apply(context, args);
        if (!timeout) context = args = null;
      }
    }
  };

  return function(...args) {
    context = this;
    timestamp = +new Date();
    const callNow = immediate && !timeout;
    // 如果延时不存在，重新设定延时
    if (!timeout) timeout = setTimeout(later, wait);
    if (callNow) {
      result = func.apply(context, args);
      context = args = null;
    }

    return result;
  };
}

深克隆

/**
 * This is just a simple version of deep copy
 * Has a lot of edge cases bug
 * If you want to use a perfect deep copy, use lodash's _.cloneDeep
 * @param {Object} source
 * @returns {Object}
 */
export function deepClone(source) {
  if (!source && typeof source !== "object") {
    throw new Error("error arguments", "deepClone");
  }
  const targetObj = source.constructor === Array ? [] : {};
  Object.keys(source).forEach(keys => {
    if (source[keys] && typeof source[keys] === "object") {
      targetObj[keys] = deepClone(source[keys]);
    } else {
      targetObj[keys] = source[keys];
    }
  });
  return targetObj;
}

设置cookie

/**
* @param {String} name
* @param {String} value
* @param {Number} days
*/
export function setCookie(name, value, days = 7) {
  var d = new Date();
  d.setTime(d.getTime() + 24 * 60 * 60 * 1000 * days);
  window.document.cookie =
  name + "=" + value + ";path=/;expires=" + d.toGMTString();
},

获取cookie

export function getCookie(name) {
    var v = window.document.cookie.match("(^|;) ?" + name + "=([^;]*)(;|$)");
    return v ? v[2] : null;
},