bitwise-article

right-identifiers-usage-example.ts

enum States {
	LOADING /***/ = 0b0000,
	FAILED /****/ = 0b0001,
	LOADED /****/ = 0b1110,
	PLAYING /***/ = 0b0100,
	STOPPED /***/ = 0b1000
}

const currentState: number = getStateSomehow(); 

/** We can use AND operation to compare the states **/

currentState & States.FAILED

// ================ //

/** We can use OR operation to check multiple states together - explanation right below **/

currentState & (States.STOPPED | States.FAILED)

/**
 * =======================
 * STOPPED : 0b 1 0 0 0
 * FAILED  : 0b 0 0 0 1
 * ============ OR =======
 * O1      : 0b 1 0 0 1  ( Stopped | Failed )
 * CURRENT : 0b 0 1 0 0  ( Playing )
 * ============ AND ======
 * O2      : 0b 0 0 0 0  ( Same identifier as loading, but it doesn't mean it ) 
 */

// ================ //

/**
 * We can use XOR to assign a new state. This is actually a bit (pun intended) out of scope,
 * since our example does not allow having a "currentState" that is the combination of multiple
 * statuses at the same time. The scope of the article was to show how can be related states be
 * combined, but states can also be unrelated (so each can have its own unique identifer) and we
 * would still be able to benefit of these feature.
 *
 * But let's fake it and let's say that PLAYING, FAILED and STOPPED can be mixed up together.
 */

currentState = currentState ^ (States.STOPPED | STATES.FAILED)

/**
 * =======================
 * STOPPED : 0b 1 0 0 0
 * FAILED  : 0b 0 0 0 1
 * ============ OR =======
 * O1      : 0b 1 0 0 1  ( Stopped | Failed )
 * CURRENT : 0b 0 1 0 0  ( Playing )
 * ============ XOR ======
 * O2      : 0b 1 1 0 1  ( Da faq is this?!)
 */