Function increasesByFunc

Export assertion functions

increasesByFunc<R, T = any>(
    this: IAssertScope,
    getter: T | (() => any),
    prop?: keyof T,
    delta?: number | MsgSource,
    evalMsg?: MsgSource,
): R
Asserts that executing the target function increases the monitored value by a specific delta. Unlike changesByFunc, the delta must be positive and the value must actually increase.
Type Parameters
- R
- T = any
Parameters
- this: IAssertScope
  The current IAssertScope object
- getter: T | (() => any)
  A function that returns a value to monitor, or an object containing the property to monitor
- Optionalprop: keyof T
  The property name to monitor (only used when first argument is an object)
- Optionaldelta: number | MsgSource
  The expected increase amount (must be a positive number)
- OptionalevalMsg: MsgSource
  Optional message to display if the assertion fails
Returns R
The current IAssertScope.that object
Example
```
let count = 5;
const getCount = () => count;
const addTen = () => { count += 10; };

expect(addTen).to.increaseBy(getCount, 10);  // Passes - increased by exactly 10
```
- Defined in assert/funcs/changesBy.ts:249