cerceis-lib/src/Generate/generate.ts

Contains list of quality of life functions that is written in TypeScript and es6

import { AlphabateOptions } from "./types";
import { FromArray } from "../FromArray/fromArray";
/**
 * Generator that generates all kinds of values.
 * alphanum
 * objectId
 * int
 * array
 */
interface generateArrayOptions{
    min?: number,
    max?: number
}
export const Generate = {
    /**
     * Generates a string consist of alphanumeric characters of given length
     * @param {number}[len=4] Length of the string 
     * @returns Alphanumeric string
     */
    alphanum(len: number = 4): string{
        const chars: string ='0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
        if(len === 1) return chars[Math.floor(Math.random() * chars.length)];
        let result = '';
        for (let i = len; i > 0; --i) result += chars[Math.floor(Math.random() * chars.length)];
        return result;
    },
     /**
     * Generates Object Id.
     * @returns 
     */
    objectId (): string{
        const timestamp: string = (new Date().getTime() / 1000 | 0).toString(16);
        return timestamp + 'xxxxxxxxxxxxxxxx'.replace(/[x]/g, () => {
            return (Math.random() * 16 | 0).toString(16);
        }).toLowerCase();
    },
    /**
     * Generates random integer in a given range of [).
     * Includes Min, exclude Max.
     * @param min 
     * @param max 
     * @returns number
     */
    int(min: number, max: number): number{
        let result: number = 0;
        result = Math.floor(Math.random() * (max - min))+ min
        return result
    },
    /**
     * Generate random number.
     * @param min 
     * @param max 
     * @returns 
     */
    random(min: number, max: number): number{
        return Math.random() * (max - min) + min;
    },
    /**
     *  Generates an array with random integer as elemnt of desired length.
     *  @param len @required Length of the array.
     *  @returns Array of a given length
     */
    array(len: number, ops:generateArrayOptions = {}){
        const defaultOps: generateArrayOptions = {
            min:0,
            max: 11,
        }
        const mergedOps: generateArrayOptions = {...defaultOps, ...ops};
        const rs: number[] = [];
        for(let i = 0; i< len ; i++)
            rs.push(this.int(mergedOps.min ?? 0, mergedOps.max ?? 11))
        return rs
    },
    /**
     * Generates random alphabate of specified length.
     * @param {number} [len=5] Length of the string. default = 5,
     * @param {AlphabateOptions} [options] Options
     */
    alphabate(
        len: number = 5,
        options: AlphabateOptions = {}
    ): string{
        const op: AlphabateOptions = {
            lowercase: true,
            uppercase: true
        }
        Object.assign(op, options);
        let result = '';
        const lowerCaseCharacters = "abcdefghijklmnopqrstuvwxyz";
        const upperCaseCharacters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        let characterPool = "";
        if(op.lowercase) characterPool += lowerCaseCharacters;
        if(op.uppercase) characterPool += upperCaseCharacters;
        const charactersLength = characterPool.length;
        for (let i = 0; i<len; i++){
            result += characterPool.charAt(Math.floor(Math.random() * charactersLength));
        }
        return result;
    },
    /**
     * @returns Current Date Time with a format of "YYYY-MM-DD""
     */
    currentDate(): string{
        const t: Date = new Date();
        return `${t.getFullYear()}-${t.getMonth()+1}-${t.getDate()}`;
    },
    /**
     * @returns Current Date Time with a format of "HH:mm:ss""
     */
    currentTime(): string{
        const t: Date = new Date();
        return `${String(t.getHours()).padStart(2,"0")}:${String(t.getMinutes()).padStart(2,"0")}:${String(t.getSeconds()).padStart(2,"0")}`;
    },
    /**
     * @returns Current Date Time with a format of "YYYY-MM-DD HH:mm:ss""
     */
    currentDateTime(): string{
        const t: Date = new Date();
        return `${t.getFullYear()}-${t.getMonth()+1}-${t.getDate()} ${String(t.getHours()).padStart(2,"0")}:${String(t.getMinutes()).padStart(2,"0")}:${String(t.getSeconds()).padStart(2,"0")}`;
    },
    /**
     * Generates and return list of date of specified day.
     * Ex: All Sunday and Monday of 2022-01-01 to 2022-03-01
     * @param f  From : YYYY-MM-DD
     * @param t  To : YYYY-MM-DD
     * @param days  number[] 0 ~ 6 Sunday ~ Saturday.
     */
    listOfDateOfDays(f: string, t: string, days: number[]){
        let fromDate = new Date(f);
        const toData = new Date(t);
        let fromISO = fromDate.toISOString();
        const toISO = toData.toISOString();
        const rs: string[] = [];
        while(true){
            if(fromISO > toISO) break;
            if(days.includes(fromDate.getDay()))
                rs.push(fromISO.slice(0,10))
            fromDate.setDate(fromDate.getDate()+1);
            fromISO = fromDate.toISOString();
        }
        return rs;
    },
    /**
     * Fast UUID generator, RFC4122 version 4 compliant.
     * Copied and rewritted from the below. Thanks for such
     * elegant code.
     * @author Jeff Ward (jcward.com).
     * @license MIT license
     * @link http://stackoverflow.com/questions/105034/how-to-create-a-guid-uuid-in-javascript/21963136#21963136
     **/
    uuidv4(){
        const lut: string[] = []; 
        for (let i=0; i<256; i++) { lut[i] = (i<16?'0':'')+(i).toString(16); }
        const d0 = Math.random()*0xffffffff|0;
        const d1 = Math.random()*0xffffffff|0;
        const d2 = Math.random()*0xffffffff|0;
        const d3 = Math.random()*0xffffffff|0;
        return (
            lut[d0&0xff]+lut[d0>>8&0xff]+lut[d0>>16&0xff]+lut[d0>>24&0xff]+'-'+
            lut[d1&0xff]+lut[d1>>8&0xff]+'-'+lut[d1>>16&0x0f|0x40]+lut[d1>>24&0xff]+'-'+
            lut[d2&0x3f|0x80]+lut[d2>>8&0xff]+'-'+lut[d2>>16&0xff]+lut[d2>>24&0xff]+
            lut[d3&0xff]+lut[d3>>8&0xff]+lut[d3>>16&0xff]+lut[d3>>24&0xff]
        );
    }
}