Fish 3.0 addresses the common `&&` and `||` operator incompatibility and if you pasted the first snippet it suggests that you should use `env`: fish: Unsupport

Fish 3.0 addresses the common `&&` and `||` operator incompatibility and if you pasted the first snippet it suggests that you should use `env`: fish: Unsupported use of '='. To run 'yarn' with a modified environment, please use 'env PORT=5000 yarn…'