/*
 * 将 nanoid/no-secure 源码内置
 * https://github.com/ai/nanoid/blob/5911e0311975810629cf3689ed8fb4b76f505113/non-secure/index.js
 */

// This alphabet uses a-z A-Z 0-9 _- symbols.
// Symbols are generated for smaller size.
// -_zyxwvutsrqponmlkjihgfedcba9876543210ZYXWVUTSRQPONMLKJIHGFEDCBA
let url = '-_';
// Loop from 36 to 0 (from z to a and 9 to 0 in Base36).
let i = 36;
while (i--) {
    // 36 is radix. Number.prototype.toString(36) returns number
    // in Base36 representation. Base36 is like hex, but it uses 0–9 and a-z.
    url += i.toString(36);
}
// Loop from 36 to 10 (from Z to A in Base36).
i = 36;
while (i-- - 10) {
    url += i.toString(36).toUpperCase();
}

export default (size = 21): string => {
    let _size = size;
    let id = '';
    // Compact alternative for `for (var i = 0; i < size; i++)`
    while (_size--) {
        // `| 0` is compact and faster alternative for `Math.floor()`
        id += url[(Math.random() * 64) | 0];
    }
    return id;
};