hookRequire passes an object to the transformer function, not a string

[kevinkir]

The hookRequire function in the hook.js file of istanbul-lib-hook does not behave as documented.

The JSDoc for hookRequire has

@param transformer {Function(code, filePath)} a function called with the original code and the associated path of the file from where the code was loaded. Should return the transformed code.

This also matches its type definition:

type Transformer = (code: string, filepath: string) => string;

However, what actually gets passed as the second argument to the transformer callback is an object that looks like this: { filename: '/the/file/path' }.

The problematic lines of code are

// hook.js#16
if (typeof options === 'string') {
    options = { filename: options };
}
// ...
// hook.js#29
transformed = transformer(code, options);

The options to fix this would be either:

• update the documentation and type interface to reflect the actual behavior
• Change hook.js#29 to transformed = transformer(code, options.filename);