千位分隔符

  1. function parseToMoney(num) {
  2.   num = parseFloat(num.toFixed(3));
  3.   let [integer, decimal] = String.prototype.split.call(num, '.');
  4.   integer = integer.replace(/\d(?=(\d{3})+$)/g, '$&,');
  6.   return integer + '.' + (decimal ? decimal : '');
  7. }

电话号码校验

  1. function isPhone(tel) {
  2.     var regx = /^1[34578]\d{9}$/;
  3.     return regx.test(tel);
  4. }

邮箱验证

  1. function isEmail(email) {
  2.     var regx = /^([a-zA-Z0-9_\-])+@([a-zA-Z0-9_\-])+(\.[a-zA-Z0-9_\-])+$/;
  3.     return regx.test(email);
  4. }

身份证验证

  1. function isCardNo(number) {
  2.   var regx = /(^\d{15}$)|(^\d{18}$)|(^\d{17}(\d|X|x)$)/;
  3.   return regx.test(number);
  4. }

字符串出现最多次数的字符

  1. function getMaxCnt(str) {
  2.   const json = {};
  3.   const maxCnt = 0;
  4.   const maxCntChar = '';
  6.   str = str.split('').sort.join('');
  7.   for(let i = 0; i < str.length - 1, i++) {
  8.     const char = str[i];
  9.     const charCnt = str.lastindexOf(char)-i+1;
  11.     if(maxCnt < charCnt) {
  12.       maxCnt = charCnt;
  13.       maxCntChar = char;
  14.     }
  16.     i = str.lastIndexOf(char);
  17.   }
  18. }
  1. // 1
  2. let a = [1, 2, 3];
  3. a.toString = a.shift;
  4. if (a == 1 && a == 2 && a == 3) {
  5.   console.log('ok');
  6. }
  8. // 2
  9. let i = 0;
  10. Object.defineProperty(window, 'a', {
  11.   get() {
  12.     return ++i;
  13.   }
  14. });
  15. if (a == 1 && a == 2 && a == 3) {
  16.   console.log('ok');
  17. }
  19. // 3
  20. let a = {
  21.   i: 0,
  22.   [Symbol.toPrimitive]() {
  23.     return ++this.i;
  24.   }
  25. };
  26. if (a == 1 && a == 2 && a == 3) {
  27.   console.log('ok');
  28. }