Needed a function which could return either a random array item or a random ranged integer or decimal value with ability to control decimal precision.

random.js

const random = ({array: a, min, max, decimal = false, decimalPrecision = 2}) => {

    if (Array.isArray(a)) return a[Math.floor(Math.random() * a.length)];

    else if ([min, max].every(n => typeof n === "number")) {

        min = Math.ceil(min),
        max = Math.floor(max);

        let num = Math.floor(Math.random() * (max - min + 1)) + min;

        if (decimal) num = (num += Math.random() * (.99 - .1) + .1).toFixed(decimalPrecision);

        return num;
    }

    else throw "Invalid arguments for random function";

}

usage-example.js

/*

For an order system where I was taked with implementing the design
before viable data was availaible. I needed
    - random past/future dates
    - random price w/ decimals
    - random picked delivery method and delivery status

*/

const mockupOrder = _ => {
    
    const
        now    = new Date(),
        past   = new Date(now.getTime() + (86400000 * -random({min: 1, max: 5}))),
        future = new Date(now.getTime() + (86400000 *  random({min: 1, max: 7})));

    return {
        registeredDate: this.formatDate(past),
        expectancyDate: this.formatDate(future),
        deliveryMethod: random({array: this.deliveryMethods}),
        deliveryStatus: random({array: this.deliveryStatuses}),
        price: this.formatPrice(random({min: 100, max: 2000, decimal: true}))
    }
    
}

/* some react component… */

this.state = {
    orders: [...Array(5)].map(_ => this.mockupOrder())
}