Align match behavior with case/== #6684
Conversation
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It doesn't look like our documentation was specific enough to cover this nuance, so it technically doesn't require an update. Does anyone think we should make it more specific?
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Yes, I think we should make the documentation more specific, assuming we don’t intend to revisit this decision anytime soon. Without additional documentation, I think some developers may still be initially surprised that I agree with this change, but the previous error message at least gave the developer a clue as to where the problem might lay. Without either the error message or documentation, the developer is left to guess that |
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Agreed re: clarifying the docs. Draft:
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| return new Match((inputType: any), (outputType: any), input, cases, outputs, otherwise); | ||
| } | ||
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| evaluate(ctx: EvaluationContext) { | ||
| const input = (this.input.evaluate(ctx): any); | ||
| return (this.outputs[this.cases[input]] || this.otherwise).evaluate(ctx); | ||
| const output = (typeOf(input) === this.inputType && this.outputs[this.cases[input]]) || this.otherwise; |
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Too bad we can't just use Map
anandthakker
added
the
breaking change ⚠️
Makes `["match", ["get", k], label, match, otherwise]` equivalent to `["case", ["==", ["get", k], label], match, otherwise]`. This changes the behavior of match expressions where the runtime type of the input does not match the type of the labels: previously such expressions produced a runtime type error and then fell back to the property default value; now they produce the fallback value from the match expression.
We can now take advantage of the relaxed typing for == and match, which allows full-fidelity conversion of categorical functions. Previously, we were relying on the default value being substituted at evaluation time if the input was not of the expected type. Now, case/match can handle that.
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@anandthakker Want to review the conversion addition here? |
Makes
["match", ["get", k], label, match, otherwise]equivalent to["case", ["==", ["get", k], label], match, otherwise]. This changes the behavior of match expressions where the runtime type of the input does not match the type of the labels: previously such expressions produced a runtime type error and then fell back to the property default value; now they produce the fallback value from the match expression.Fixes #6680.
cc @mapbox/studio @mapbox/maps-design @mapbox/ios @mapbox/android
Launch Checklist
@mapbox/studioand/or@mapbox/maps-designif this PR includes style spec changes