[iOS] Crash when assigning values to lineDasharray, iconTextFitPadding

[rnmapbox]

[iOS] Crash when assigning values to lineDasharray, iconTextFitPadding

[mfazekas]

@mattijsf thanks for the report. Not yet looked into, does ["literal", [...]] works?

[mattijsf]

Yes @mfazekas that works! Good to have a workaround available!

I just checked the Android's RCTMGLStyleFactory there we use the following logic:

public static void setLineDasharray(LineLayer layer, RCTMGLStyleValue styleValue) {
  if (styleValue.isExpression()) {
    layer.setProperties(PropertyFactory.lineDasharray(styleValue.getExpression()));
  } else {
    layer.setProperties(PropertyFactory.lineDasharray(styleValue.getFloatArray(VALUE_KEY)));
  }
}

Seems like we could use a similar isExpression technique on iOS to map it towards a plain array instead.

[mattijsf]

- (NSExpression *)mglStyleValue`
{
    ...
    ...
    } else if ([expressionJSON respondsToSelector:@selector(objectEnumerator)] && [[[(NSArray*)expressionJSON objectEnumerator] nextObject] isKindOfClass:[NSNumber class]]) {
        return [NSExpression expressionForConstantValue:expressionJSON];
    } else {
        return [NSExpression expressionWithMGLJSONObject:expressionJSON];
    }
}

This expressionForConstantValue:expressionJSON addition in RCTMGLStyleValue.m works for the lineDashPattern case. My idea was that when the first element of the expression (array) is a number we can safely assume it is an array of constant values.

iconTextFitPadding is special since it needs to be an instance of UIEdgeInsets so extending styleExtras in styleMap.js with a extra entry: iconTextFitPadding: { iosType: 'edgeinsets' } will do the trick.

If you would like. I could create a PR for these changes. I also noticed the edgeinsets check in RCTMGLStyleValue.mglStyleValue is broken. It should check for the presence of an array.