I'm reading the [react-redux documentation](https://github.com/reactjs/react-redux/blob/master/docs/api.md#arguments) and I found this:

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> [mapStateToProps(state, [ownProps]): stateProps] (Function)
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> 
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I don't understand exactly what "**[ ]**" means, or what is the "**:**" symbol used for in this context. 
I remember that jQuery also uses this for it's API documentation. Example: 

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> .slideToggle([duration][,complete])
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Is there any convention for writing/reading these?