Function abbreviate

abbreviate(
    text?: null | string,
    width?: number,
    placeholder?: string,
): undefined | null | string
Returns a string that abbreviates the given text using placeholder
Parameters
- Optionaltext: null | string
  the text to inspect
- width: number = -1
  the max width of the expected string
- placeholder: string = '...'
  the placeholder to append
Returns undefined | null | string
a string that abbreviates the given text using placeholder
Author
David Hsing
Example
```
abbreviate('foobar', -1);    // 'foobar'
abbreviate('foobar', 0);    // ''
abbreviate('foobar', 5);    // 'fo...'
abbreviate('foobar', 6);    // 'foobar'
abbreviate('foobar', 10);    // 'foobar'
```