function generate(count) {
var founded = false,
_sym = 'abcdefghijklmnopqrstuvwxyz1234567890',
str = '';
while(!founded) {
for(var i = 0; i < count; i++) {
str += _sym[parseInt(Math.random() * (_sym.length))];
}
base.getID(string, function(err, res) {
if(!res.length) {
founded = true; // How to do it?
}
});
}
return str;
}
如何设置一个变量值与数据库查询回调?我该怎么做呢?
当前回答
你可以使用urid包npm安装urid
import urid from 'urid';
urid(); // qRpky22nKJ4vkbFZ
阅读完整的文档:https://www.npmjs.com/package/urid
// Set the size
urid(8); //ZDJLC0Zq
// Use the character set
urid('num'); // 4629118294212196
urid('alpha'); // ebukmhyiagonmmbm
urid('alphanum'); // nh9glmi1ra83979b
// Use size with character set
urid(12, 'alpha'); // wwfkvpkevhbg
// use custom character set
urid(6, '0123456789ABCDEF'); // EC58F3
urid('0123456789ABCDEF'); // 6C11044E128FB44B
// some more samples
urid() // t8BUFCUipSEU4Ink
urid(24) // lHlr1pIzAUAOyn1soU8atLzJ
urid(8, 'num') // 12509986
urid(8, 'alpha') // ysapjylo
urid(8, 'alphanum') // jxecf9ad
// example of all character sets
urid('num') // 5722278852141945
urid('alpha') // fzhjrnrkyxralgpl
urid('alphanum') // l5o4kfnrhr2cj39w
urid('Alpha') // iLFVgxzzUFqxzZmr
urid('ALPHA') // ALGFUIJMZJILJCCI
urid('ALPHANUM') // 8KZYKY6RJWZ89OWH
urid('hex') // 330f726055e92c51
urid('HEX') // B3679A52C69723B1
// custom character set
urid('ABCD-') // ACA-B-DBADCD-DCA
其他回答
安装NPM uuid包(来源:https://github.com/uuidjs/uuid):
npm install uuid
并在你的代码中使用它，例如ES6导入:
import { v4 as uuidv4, v6 as uuidv6 } from 'uuid';
uuidv4();
uuidv6();
或者使用CommonJS需要:
const {
v1: uuidv1,
v4: uuidv4,
} = require('uuid');
uuidv1(); // -> '6c84fb90-12c4-11e1-840d-7b25c5ee775a'
uuidv4(); // -> '110ec58a-a0f2-4ac4-8393-c866d813b8d1'
For
编辑:shortid已弃用。维护者建议使用纳米体代替。
另一种方法是使用npm中的shortid包。
它非常容易使用:
var shortid = require('shortid');
console.log(shortid.generate()); // e.g. S1cudXAF
它有一些引人注目的特点:
ShortId创建惊人的短非顺序url友好的唯一 id。完美的url缩短器，MongoDB和Redis id，和任何其他 用户可能看到的Id。 默认7-14个url友好字符:A-Z, A-Z, 0-9， _- 非连续的，所以它们是不可预测的。 可以生成任意数量的id而不重复，甚至每天数百万。 应用程序可以重新启动任意次数，没有任何重复id的机会。
对我来说，获取唯一id的最简单方法是时间，我在这个例子中使用哈希
const hash = require('object-hash');
const user = { ..., iat: Date.now() }
const user_id = hash(user)
console.log(user_id) // ex. 49686bab1a2276e0b1bd61ccc86f8156
这就是我在任何方面获得唯一标识符的方法。因为在现实世界中，时间是不会重复的。
如果有人需要加密强UUID，也有解决方案。
https://www.npmjs.com/package/generate-safe-id
npm install generate-safe-id
Why not UUIDs? Random UUIDs (UUIDv4) do not have enough entropy to be universally unique (ironic, eh?). Random UUIDs have only 122 bits of entropy, which suggests that a duplicate will occur after only 2^61 IDs. Additionally, some UUIDv4 implementations do not use a cryptographically strong random number generator. This library generates 240-bit IDs using the Node.js crypto RNG, suggesting the first duplicate will occur after generating 2^120 IDs. Based on the current energy production of the human race, this threshold will be impossible to cross for the foreseeable future.
var generateSafeId = require('generate-safe-id');
var id = generateSafeId();
// id == "zVPkWyvgRW-7pSk0iRzEhdnPcnWfMRi-ZcaPxrHA"
节点uuid已弃用，请使用uuid
npm install uuid --save
// Generate a v1 UUID (time-based)
const uuidV1 = require('uuid/v1');
uuidV1(); // -> '6c84fb90-12c4-11e1-840d-7b25c5ee775a'
// Generate a v4 UUID (random)
const uuidV4 = require('uuid/v4');
uuidV4(); // -> '110ec58a-a0f2-4ac4-8393-c866d813b8d1'
Npm链接
