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Number.isInteger() – How to Check If a Number Is an Integer

Number.isInteger() checks if its argument is an integer. If so, it returns true. Otherwise, the method returns false.

Syntax of the Number.isInteger() Method

Number.isInteger() accepts only one required argument. Here is the syntax:

Number.isInteger(value);

The value argument represents the item you wish to test if it is an integer.

Examples of the Number.isInteger() Method

Below are examples of the Number.isInteger() method.

Is 578 an integer?

Number.isInteger(578);
// The invocation above will return: true

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Is 0.99 an integer?

Number.isInteger(0.99);
// The invocation above will return: false

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Is "test" an integer?

Number.isInteger("test");
// The invocation above will return: false

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Is negative 300 an integer?

Number.isInteger(-300);
// The invocation above will return: true

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Is zero an integer?

Number.isInteger(0);
// The invocation above will return: true

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Is Math.PI an integer?

Number.isInteger(Math.PI);
// The invocation above will return: false

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