Add Map predicate #36
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source/lib/predicates/map.ts
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| */ | ||
| hasKeys(...keys: any[]) { | ||
| return this.addValidator({ | ||
| message: map => `Expected Map to have all keys of \`${JSON.stringify(keys)}\`, got \`${JSON.stringify(Array.from(map.keys()))}\``, |
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What do you think about stringifying only 3 items, for example? This is to prevent error message being really long, because the whole array and map get serialized. So if keys.length > 3, show all keys of [1, 2, 3, ...].
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Yes I wasn't sure about the error message either. Maybe we should be more specific and show which key could not be found? Because if we only show the first 3 items, the message could look like
Expected Map to have all keys of
[1, 2, 3, ...], got[1, 2, 3, ...]
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Great suggestion. Expected Map to have keys [1, 2, 3]?
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Expected Map to have keys [1, 2, 3]?
👍
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I'm looking into this and what we didn't consider was that testing this could cause a performance issue on very large datasets. Not sure if we should take this into account?
What I mean is that .every() exits early when one of the items don't match. Determining which keys are missing in the map requires us to iterate over the entire array.
So either we go with that approach, or we take a different one. We could also exit early and just show the error message
Expected Map to have key
1
The downside is that maybe, key 2 is missing as well, but because we exited early (on the first mismatch), we don't know for sure.
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I would also be fine with showing the first 3-5 to be honest. But no strong opinion on the amount.
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Ok. Let’s show the first 5.
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What if map's values aren't just numbers? Error message will be huge in that case. Not sure yet what's the best solution here.
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I totally agree, I just think this would be very difficult to do well with complex datastructures. Maybe we can just go with the showing the first 5 and improve later on, gather some feedback from users etc.
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Agreed. Let's do it simple for now and we can use some more elaborate heuristics when we get some user feedback.
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Updated the methods! |
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Looks great, as always! :) |
Implemented everything regarding
Map.