The combination of JavaScript and operators and or operators

If else is used to implement (add_step change) under different conditions, the add_level result value is different:
Copy codeThe Code is as follows:
Var add_level = 0;
If (add_step = 5 ){
Add_level = 1;
}
Else if (add_step = 10 ){
Add_level = 2;
}
Else if (add_step = 12 ){
Add_level = 3;
}
Else if (add_step = 15 ){
Add_level = 4;
}
Else {
Add_level = 0;
}

1) the above functions can also be implemented through switch:
Copy codeThe Code is as follows:
Var add_level = 0;
Switch (add_step ){
Case 5: add_level = 1;
Break;
Case 10: add_level = 2;
Break;
Case 12: add_level = 3;
Break;
Case 15: add_level = 4;
Break;
Default: add_level = 0;
Break;

2) ctictipt is implemented through | and:
Copy codeThe Code is as follows:
Var add_level = (add_step = 5 & 1) | (add_step = 10 & 2) | (add_step = 12 & 3) | (add_step = 15 & 4) | 0;

3) The 2nd types of writing can also be abbreviated:
Copy codeThe Code is as follows:
Var add_level = {'5': 1, '10': 2, '12': 3, '15': 4} [add_step] | 0;

A basic formula can be obtained from the 2nd write methods:
Copy codeThe Code is as follows:
Add_step = 5 & add_level = 1

Equivalent to <=>
Copy codeThe Code is as follows:
If (add_step = 5 ){

Add_level = 1

}