具有三个变量的短路评估

Question

I wrote the following code, thinking it would fail to work because it would go like this: "if it is not running and the ID matches this one, execute the code" disregarding the cap on the break size:

if(!isRunning && id==="break-increment" && breakvar<=59){
this.setState((state) => ({
  break: this.state.break +1}))}

Much to my surprise, it worked. But I don´t really understand why. Wouldn´t it fail because the cap size would never be evaluated?

Answer 1

I thought you couldn´t have three conditions without short-circuiting (eg, if isRunning is false then it only evaluates id)

No.

If !isRunning is false, the first && short circuits and is evaluated as its LHS (false) without evaluating the RHS.

If !isRunning is true, the first && doesn't short circuit and is evaluated as its RHS ( id==="break-increment" && breakvar<=59 )