Simplify nested if/else with repeated results?

Question

I'm trying to simplify the following:

function handleDirection(src) {   if (src === 'left') {     if (inverse) {       tracker--;     } else {       tracker++;     }   } else {     if (inverse) {       tracker++;     } else {       tracker--;     }   } } 

to reduce the number of conditionals. The src will either be 'left' or 'right' always.

Answer 1

You could check with the result of the first check.

This is an exclusive OR check.

// typeof inverse === 'boolean'  function handleDirection(src) {     if (src === 'left' === inverse) {         tracker--;     } else {         tracker++;     } } 

The check evaluates the expression in this order (src === 'left') === inverse:

src === 'left' === inverse ---- first ---             returns a boolean value --------- second --------- take result of former check & compairs it with another boolean 

Answer 2

function handleDirection(src) {    var movement = 1;    if(src === 'left')      movement = -1;     if(inverse)      tracker += movement;    else      tracker -= movement; }