Function weighted_histo_key

weighted_histo_key(
    n: number,
    opts: any[],
    prob_prop: string,
    extract: string,
    rng?: JssmRng,
): Map<any, number>
Draws n weighted random samples, extracts a named key from each, and returns a histograph (Map) of how often each key value appeared. Useful for validating that a probabilistic transition distribution is roughly correct over many trials.
```
const opts = [
  { to: 'a', probability: 0.7 },
  { to: 'b', probability: 0.3 }
];

weighted_histo_key(1000, opts, 'probability', 'to');
// Map { 'a' => ~700, 'b' => ~300 }
```
Parameters
- n: number
  Number of samples to draw.
- opts: any[]
  Non-empty array of weighted objects.
- prob_prop: string
  Name of the numeric weight property.
- extract: string
  Name of the property to extract from each sample for histogramming.
- Optionalrng: JssmRng
  Optional random number generator.
Returns Map<any, number>
A Map from extracted key values to their occurrence counts.
- Defined in src/ts/jssm_util.ts:300