Feature request: jscodeshift output from arbitrary input

AST explorer is (most?) often used when building jscodeshift codemods. Would be great if the tool supported something like this:

input: `a => b`
output:

```
j.arrowFunctionExpression(
[j.identifier('a')],
j.identifier('b')
)
```

This would speed up the development of jscodeshift codemods enormously.