I2c constants

Are these constants still valid? https://electricimp.com/docs/api/hardware/i2c/readerror/

I get ERROR: the index 'NO_ERROR' does not exist


That page is in error. There are no constants for those values; you just have to use the numbers instead.

The numbers are for debugging purposes only, and the range of values produced may change from release to release, so there’s not much point making constants for them.