How Can I Efficiently Check if a Variable Equals One of Multiple Values in JavaScript?

Simplify Variable Equality Checks Against Multiple Values

When checking a variable for equality with multiple values, a simple solution might involve an if statement with multiple conditions. However, this can become verbose.

An alternative approach is to define an object and use the in operator. However, this requires manually assigning redundant values to each item:

if( foo in {1: 1, 3: 1, 12: 1} ) {
    // ...
}

A Cleaner Option

In ECMA2016, JavaScript introduces the includes method on arrays. This provides a straightforward and concise solution:

if([1,3,12].includes(foo)) {
    // ...
}

This code checks if the value of foo is included in the array. If it is, the condition evaluates to true. This method is supported by all major browsers, making it a widely applicable solution.

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