Function perSecond

perSecond(
amount: number,
options?: Partial<{ clamp: boolean; max: number; min: number }>,
): ModSource
Returns a proportion of amount depending on elapsed time. Cumulatively, amount is yielded every second.
```
// Calculate a proportion of 0.1 every second
const x = perSecond(0.1);
x();
```
The faster x() is called, the smaller the chunks of amount are returned. Values accumulate. For example, x() isn't called for two seconds, 2*amount is returned.
Parameters
- amount: number
- options: Partial<{ clamp: boolean; max: number; min: number }> = {}
Returns ModSource
Example: Usage
```
const settings = {
 ageMod: perSecond(0.1);
};

let state = {
 age: 1
};

// Update
setInterval(() => {
 let { age } = state;
 // Add 0.1 per second, regardless of 
 // loop speed
 age += settings.ageMod(); 
 state = {
   ...state,
   age: clamp(age)
 }
});
```
Use the clamp option so the returned value never exceeds amount. Alternatively, min/max options allow you to set arbitrary limits.