Odtnhj

Looking at the code for React.Children.map, it looks like the function takes up to 3 args.

The api doc for React.Children.map shows

React.Children.map(children, function[(thisArg)])

If it can take 3 args I expected to see 2 commas in there somewhere.

My question is

How do you read React.Children.map(children, function[(thisArg)]) in plain english?

So far I have "React.Children.map is a function that..."

function[(thisArg)] isn't a standard denotation. As the documentation states, map

Invokes a function on every immediate child contained within children with this set to thisArg.

Children.map signature is similar to JavaScript Array.prototype.map. There are 3 arguments, 3rd argument is optional this context for callback function if needed.

Children.map is documented better in source code:

/**
 * Maps children that are typically specified as `props.children`.
 *
 * See https://reactjs.org/docs/react-api.html#reactchildrenmap
 *
 * The provided mapFunction(child, key, index) will be called for each
 * leaf child.
 *
 * @param ?* children Children tree container.
 * @param function(*, int) func The map function.
 * @param * context Context for mapFunction.
 * @return object Object containing the ordered map of results.
 */
function mapChildren(children, func, context) ...