Merge branch 'mapperMap' into 'master'

Add Mapper.map

Closes #104

See merge request kado/kado!311
4 jobs for master in 2 minutes and 32 seconds (queued for 9 seconds)
Status Name Job ID Coverage
  Test
passed node10 #9406

00:00:38

passed node12 #9408

00:00:40

passed node14 #9410

00:00:35

passed node-latest #9412

00:00:37