驼峰名转下划线：
‘componentMapModelRegistry’.match(/^[a-z][a-z0-9]+|[A-Z][a-z0-9]*/g).join(‘_’).toLowerCase(); // component_map_model_registry
获取 URL 参数
function wordCount(data) {
var pattern = /[a-zA-Z0-9_\u0392-\u03c9]+|[\u4E00-\u9FFF\u3400-\u4dbf\uf900-\ufaff\u3040-\u309f\uac00-\ud7af]+/g;
var m = data.match(pattern);
var count = 0;
if(m === null) return count;
for (var i = 0; i < m.length; i++) {
if (m[i].charCodeAt(0) >= 0x4E00) {
count += m[i].length;
} else {
count += 1;
}
}
return count;
}
var text = ‘ 贷款买房，也意味着你能给自己的资产加杠杆，能够撬动更多的钱，来孳生更多的财务性收入。’;
wordCount(text); // 38
特殊字符转义
function htmlspecialchars (str) {
var str = str.toString().replace(/&/g, “&”).replace(/</g, “<”).replace(/>/g, “>”).replace(/”/g, ‘"’);
return str;
}
htmlspecialchars(‘&jfkds<>’); // “&jfkds<>”
格式化数量
// 方法一
function formatNum (num, n) {
if (typeof num == “number”) {
num = String(num.toFixed(n || 0));
var re = /(-?\d+)(\d{3})/;
while (re.test(num)) num = num.replace(re, “$1,$2”);
return num;
}
return num;
}
formatNum(2313123, 3); // “2,313,123.000”
// 方法二
‘2313123’.replace(/\B(?=(\d{3})+(?!\d))/g, ‘,’); // “2,313,123”
// 方法三
function formatNum(str) {
return str.split(”).reverse().reduce((prev, next, index) => {
return ((index % 3) ? next : (next + ‘,’)) + prev
});
}
测试质数
var arr = ‘abcdaabc’;
var info = arr
.split(”)
.reduce((p, k) => (p[k]++ || (p[k] = 1), p), {});
console.log(info); //{a: 3, b: 2, c: 2, d: 1}
如何优雅的实现金钱格式化：1234567890 –> 1,234,567,890
var test1 = ‘1234567890’
var format = test1.replace(/\B(?=(\d{3})+(?!\d))/g, ‘,’)
console.log(format) // 1,234,567,890
代码来自于收集，方便学习