exact_change.ts

function checkCashRegister(price, cash, cid) {
  
    const units = [
        {unit: 'ONE HUNDRED', cents: 10000},
        {unit: 'TWENTY', cents: 2000},
        {unit: 'TEN', cents: 1000},
        {unit: 'FIVE', cents: 500},
        {unit: 'ONE', cents: 100},
        {unit: 'QUARTER', cents: 25},
        {unit: 'DIME', cents: 10}, 
        {unit: 'NICKEL', cents: 5}, 
        {unit: 'PENNY', cents: 1},
    ];
    
    type cashDrawer = { 
        hash:{
            [k:string]: number
        }
        total: number
    };
    
    const drawer: cashDrawer = cid.reduce((prev:cashDrawer, curr) => {
        const unit = curr[0], dollars = curr[1];    
        let hash = prev.hash;
        prev.total += dollars * 100;
        
        switch(unit) {
            case 'ONE HUNDRED': hash[unit] = dollars / 10000; break;
            case 'TWENTY': hash[unit] = dollars / 2000; break;
            case 'TEN': hash[unit] = dollars / 1000; break;
            case 'FIVE': hash[unit] = dollars / 500; break;
            case 'ONE': hash[unit] = dollars; break;
            case 'QUARTER': hash[unit] = Math.ceil(dollars * 100)/25  ; break;
            case 'DIME': hash[unit] = Math.ceil(dollars * 100)/10; break;
            case 'NICKEL': hash[unit] = Math.ceil(dollars * 100)/5; break;
            case 'PENNY': hash[unit] = Math.ceil(dollars * 100); break;
        }
        
        return prev;
    }, { total : 0, hash: {} });
    
    console.log(drawer);
    
    const getFromDrawer = (unit, amount) => {
        if (drawer[unit] < amount) {
            return drawer[unit]
        } else {
            return amount;
        }
    }
    
    const centsToNotes = (cents: number) => {
        let res = [];
        for (let i = 0; i < units.length && cents > 0; i+=1) {
            let notes = cents / units[i].cents | 0;
            if (notes) {
                notes = getFromDrawer(units[i].unit, notes);
                res.push([
                    units[i].unit,
                    notes * (units[i].cents / 100) 
                ]);
                cents -= notes * units[i].cents;
            }
        }
        if (cents > 0) {
            return [];
        } else {
            return res;
        }
    }
    
    const change = 
    
}

// Example cash-in-drawer array:
// Denominations            dollar                  cent/penny
//=========================================================================
// [["PENNY", 1.01],        1/100
// ["NICKEL", 2.05],        5/100
// ["DIME", 3.10],          10/100
// ["QUARTER", 4.25],       25/100
// ["ONE", 90.00],          1
// ["FIVE", 55.00],         1 * 5
// ["TEN", 20.00],          1 * 10
// ["TWENTY", 60.00],       1 * 20
// ["ONE HUNDRED", 100.00]] 1 * 100

checkCashRegister(19.50, 20.00, [["PENNY", 1.01], ["NICKEL", 2.05], ["DIME", 3.10], ["QUARTER", 4.25], ["ONE", 90.00], ["FIVE", 55.00], ["TEN", 20.00], ["TWENTY", 60.00], ["ONE HUNDRED", 100.00]]);