Optimize OR in IF

Question

I have a code like this:

if (action == \'John\' || action == \'John Beckham\' || action == \'Henry John\'){
     alert(\'true!\');
}

How do I m

Answer 1

If "John" always appears, the simplest thing is:

if (action.toLowerCase().indexOf("john") !== -1) {
    // Do something
}

...but as your question has already changed the values against which you're checking action once, I hesitate to assume that. Also note that it will match "xxxjohnxxx", which may not be what you want.

Original suggestions (updated for new action values from your edit):

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There are lots of ways, all shown using case insensitivity since you mentioned that in the comments:

String#indexOf:

if ("|john|john beckham|john henry|giggs john|scholes john|john messi|".indexOf("|" + action.toLowerCase() + "|") !== -1) {
    // Do something
}

---

Regular expressions:

if (/^(?:John|John Beckham|John Henry|Giggs John|Scholes John|John Messi)$/i.test(action)) {
    // Do something
}

Because you're just using the true/false result, I'm using test which just returns true/false, instead of exec which returns matching results. Both work in this case, but the browser may be able to ever-so-slightly optimize test (but then, regex is unlikely to be the best solution if your goal is the fastest result or the least memory use).

---

Or a switch:

switch (action.toLowerCase()) {
    case "john":
    case "john beckham":
    case "john henry":
    case "giggs john":
    case "scholes john":
    case "john messi":
        // Do something
}

---

Or an object lookup:

var actions = {
    "john":         true,
    "john beckham": true,
    "john henry":   true,
    "giggs john":   true,
    "scholes john": true,
    "john messi":   true
};

if (actions[action.toLowerCase()]) {
    // do something
}

(That also has the advantage of letting you say what to do — e.g., the true could be replaced with a function you call.)

---

Or (on an ES5-enabled environment or with an ES5 shim) Array#indexOf:

if (["john", "john beckham", "john henry", "giggs john", "scholes john", "john messi"].indexOf(action.toLowerCase()) !== -1 {
    // Do something
}

or since you use jQuery, you can avoid the shim on older browsers by using inArray:

if ($.inArray(action.toLowerCase(), ["john", "john beckham", "john henry", "giggs john", "scholes john", "john messi"]) !== -1) {
    // Do something
}