The law across all common law provinces seems to be that if an employee is terminated before the end of a fixed term contract and there is no valid early termination clause, then the employee is entitled to be paid for the balance of the unexpired term .
Secondly there seems to be a consensus that there is no duty for the employee to mitigate his or her damages. She can sit at home and collect her money.
But what if the employee does actually mitigate and earns income? After all, dismissed employees still have to eat while the court case goes on.
In Ontario it would seem that this income is not deducted but at least in BC and Saskatchewan it seems it is .
This is all discussed in great detail in Crook v Duxbury, 2020 SKCA 43.
Maybe one day the SCC will sort this out.