function parse(json) {
    return fromJson(JSON.parse(json));
}
Parses a JSON string into a [[Theme]] with formatter functions.

```ts
import * as fs from 'fs';
import {parse, highlight} from 'cli-highlight';

fs.readFile('mytheme.json', 'utf8', (err: any, json: string)  => {
    if (err) throw err;
    const code = highlight('SELECT * FROM table', {theme: parse(json)});
    console.log(code);
});
```