Implementation example of generating GUID using native JavaScript_javascript skills

GUID (Globally Unified Identifier) ​​refers to a number generated on one machine, which is guaranteed to be unique to all machines in the same time and space. Usually the platform will provide an API to generate GUID. The generation algorithm is interesting, using the Ethernet card address, nanosecond time, chip ID and many possible numbers. The only drawback of GUID is that the resulting string will be relatively large.

The format of GUID is: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

Everyone knows that GUID is not very useful in front-end development, but if you need to insert an ID, and this ID corresponds to the backend and other operations that require a GUID, we can still generate a GUID for convenience.

Generally, it is very simple to generate GUID in backend or database languages ​​such as sql, java, C#, etc. However, there is no way to directly generate GUID on the front end, so you can only write one by yourself. But because the GUID needs to obtain the address of the Ethernet card, as well as nanosecond-level time and other numbers. It is difficult for the front-end to obtain this information (please tell me if you know it), but we can simulate and generate GUID, the code is as follows:

/*
* Function: Generate a GUID code, where the GUID consists of less than 14 dates and times and more than 18 hexadecimal random numbers. There is a certain probability of repetition of the GUID, but the repetition probability is extremely low. Theoretically, the repetition probability is every 10ms. 1/(16^18), that is, 1/(16 to the 18th power), the probability of repetition is as low as negligible*/

function GUID() {
this.date = new Date();

/* 判断是否初始化过，如果初始化过以下代码，则以下代码将不再执行，实际中只执行一次 */
if (typeof this.newGUID != 'function') {

/* 生成GUID码 */
GUID.prototype.newGUID = function() {
this.date = new Date();
var guidStr = '';
sexadecimalDate = this.hexadecimal(this.getGUIDDate(), 16);
sexadecimalTime = this.hexadecimal(this.getGUIDTime(), 16);
for (var i = 0; i < 9; i++) {
guidStr += Math.floor(Math.random()*16).toString(16);
}
guidStr += sexadecimalDate;
guidStr += sexadecimalTime;
while(guidStr.length < 32) {
guidStr += Math.floor(Math.random()*16).toString(16);
}
return this.formatGUID(guidStr);
}

/*
* 功能：获取当前日期的GUID格式，即8位数的日期：19700101
* 返回值：返回GUID日期格式的字条串
*/
GUID.prototype.getGUIDDate = function() {
return this.date.getFullYear() + this.addZero(this.date.getMonth() + 1) + this.addZero(this.date.getDay());
}

/*
* 功能：获取当前时间的GUID格式，即8位数的时间，包括毫秒，毫秒为2位数：12300933
* 返回值：返回GUID日期格式的字条串
*/
GUID.prototype.getGUIDTime = function() {
return this.addZero(this.date.getHours()) + this.addZero(this.date.getMinutes()) + this.addZero(this.date.getSeconds()) + this.addZero( parseInt(this.date.getMilliseconds() / 10 ));
}

/*
* 功能: 为一位数的正整数前面添加0，如果是可以转成非NaN数字的字符串也可以实现
* 参数: 参数表示准备再前面添加0的数字或可以转换成数字的字符串
* 返回值: 如果符合条件，返回添加0后的字条串类型，否则返回自身的字符串
*/
GUID.prototype.addZero = function(num) {
if (Number(num).toString() != 'NaN' && num >= 0 && num < 10) {
return '0' + Math.floor(num);
} else {
return num.toString();
}
}

/* 
* 功能：将y进制的数值，转换为x进制的数值
* 参数：第1个参数表示欲转换的数值；第2个参数表示欲转换的进制；第3个参数可选，表示当前的进制数，如不写则为10
* 返回值：返回转换后的字符串
*/
GUID.prototype.hexadecimal = function(num, x, y) {
if (y != undefined) {
return parseInt(num.toString(), y).toString(x);
} else {
return parseInt(num.toString()).toString(x);
}
}

/*
* 功能：格式化32位的字符串为GUID模式的字符串
* 参数：第1个参数表示32位的字符串
* 返回值：标准GUID格式的字符串
*/
GUID.prototype.formatGUID = function(guidStr) {
var str1 = guidStr.slice(0, 8) + '-',
str2 = guidStr.slice(8, 12) + '-',
str3 = guidStr.slice(12, 16) + '-',
str4 = guidStr.slice(16, 20) + '-',
str5 = guidStr.slice(20);
return str1 + str2 + str3 + str4 + str5;
}
}
}

GUID Object

Just save it in a JS file and reference it.

Then we just need to

　var guid = new GUID();

alert(guid.newGUID());

You can get the GUID code.

The implementation principle is very simple. Here we just use the system time and more than 18 hexadecimal random numbers, and use the system time to convert to hexadecimal. Although it is still possible to repeat, the probability of repetition is extremely low. , can be ignored.