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anselrognlie
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anselrognlie
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Looks good! Please review my comments, and let me know if you have any questions. Nice job!
| body: PropTypes.string.isRequired, | ||
| timeStamp: PropTypes.string.isRequired, | ||
| liked: PropTypes.bool.isRequired, | ||
| onLikeEntry: PropTypes.func.isRequired, |
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The id, sender, body, timeStamp, and liked props are always passed (they're defined explicitly in the data and also provided in the test) so we can (and should) mark them isRequired.
The remaining props were up to you, and the tests don't know about them. As a result, using isRequired causes a warning when running any tests that only pass the known props. If you didn't see those warnings when running the tests, be sure to also try running the terminal npm test since the warnings are more visible.
To properly mark any other props isRequired, we would also need to update the tests to include at least dummy values (such as an empty callback () => {} for the like handler) to make the proptype checking happy.
Alternatively, for any props that we leave not required, we should also have logic in our component to not try to use the value if it's undefined.
| <p className="entry-time">Replace with TimeStamp component</p> | ||
| <button className="like">🤍</button> | ||
| <p>{body}</p> | ||
| <p className="entry-time"><TimeStamp time={timeStamp}/></p> |
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Nice use of the supplied TimeStamp. We pass in the timeStamp string from the message data and it takes care of the rest. All we had to do was confirm the name and type of the prop it was expecting (which we could do through its PropTypes) and we're all set!
| timeStamp: PropTypes.string.isRequired, | ||
| liked: PropTypes.bool.isRequired | ||
| })).isRequired, | ||
| onLikeEntry: PropTypes.func.isRequired, |
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Similar to the props for ChatEntry here, the entries prop is included in the tests, but the like toggle is not, resulting in prop warnings (unless we update the tests to reflect our custom props).
Again, if we were to leave this as not required so as to avoid the test warnings, we'd want to be sure that all the script logic in our component worked properly even in the absence of this value.
| key={entry.id} | ||
| id={entry.id} |
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👍 The key attribute is important for React to be able to detect certain kinds of data changes in an efficient manner. We're also using the id for our own id prop, so it might feel redundant to pass both, but one is for our logic and one is for React internals (we can't safely access the key value in any meaningful way).
| import ChatEntry from './ChatEntry'; | ||
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| const ChatLog = (props) => { | ||
| const chatEntryComponents = props.entries.map((entry) => { |
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Nice use of map to convert from the message data into ChatEntry components. We can perform this mapping storing the result into a variable we use in the JSX result as you did here (components are functions, so we can run JS code as usual before we reach the return, and even sometimes have multiple return statements with different JSX), we could make a helper function that we call as part of the return, or this expression itself could be part of the return JSX, which I often like since it helps me see the overall structure of the component, though it can make debugging a little more tricky. But any of those approaches will work fine.
| setEntries((entries) => { | ||
| return entries.map((entry) => { | ||
| if (entry.id === id) { | ||
| return {...entry, liked: !entry.liked}; | ||
| } else { | ||
| return entry; | ||
| } | ||
| }); | ||
| }); |
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Nice use of the callback setter style. In this application, it doesn't really matter whether we use the callback style or the value style, but it's good practice to get in the habit of using the callback style.
We showed this approach in class, but technically, we're mixing a few responsibilities here. rather than this function needing to know how to change the liked status itself, we could move this update logic to a helper function. This would better mirror how we eventually update records when there's an API call involved.
In this project, our messages are very simple objects, but if we had more involved operations, it could be worthwhile to create an actual class with methods to work with them, or at least have a set of dedicated helper functions to centralize any such mutation logic.
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| const likeEntry = (id) => { | ||
| setEntries((entries) => { | ||
| return entries.map((entry) => { |
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Nice use of map here to both handle making a new list so that React sees the message data has changed, and make new data for the clicked message with its like status toggled.
| const calculateLikedCount = (entries) => { | ||
| let likedCount = 0; | ||
| for (const entry of entries) { | ||
| if (entry.liked) { | ||
| likedCount++; | ||
| } | ||
| } | ||
| return likedCount; | ||
| }; |
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Nice job determining the total likes based on the like data of each message. We don't need an additional piece of state to track this, since it can be derived from the existing state we are tracking.
Explicitly totalling the count is perfectly fine, but many JS programmers would use reduce to achieve this.
const calculateLikedCount = (entries) => {
return entries.reduce((likedCount, entry) => {
return entry.liked ? likedCount + 1 : likedCount;
}, 0);
};The first few times we work with reduce, it can be challenging to understand, but it's a tool that gets used commonly enough that it's worth practicing.
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| const ChatEntry = ({id, sender, body, timeStamp, liked, onLikeEntry}) => { | ||
| const emoji = liked ? '❤️' : '🤍'; | ||
| const entrySender = sender === 'Vladimir' ? 'local' : 'remote'; |
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Nice logic to decide whether to treat a message as local or remote. How could we generalize this so that it didn't need to look explicitly for Vladimir? This project only passes in a single conversation, but ideally, our components should work in other situations.
In the general case, does the ChatEntry itself have enough information as it is to "know" which messages are local and which are remote?
| import PropTypes from 'prop-types'; | ||
| import ChatEntry from './ChatEntry'; | ||
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| const ChatLog = (props) => { |
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ChatLog uses a single props param, but ChatEntry uses a destructured object. Personally, I prefer the destructured style, since it makes the expected component attributes a bit more clear. And it's fine to use a mixture of styles in this project, but in general, try to pick one style or the other.
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