isInteger()

isInteger(value): boolean

Checks if value is an integer.

DEPRECATED

Use Number.isInteger() directly instead.

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Parameters

value: unknown

The value to check.

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Returns: boolean

true if value is an integer, else false.

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See Also

• Number.isInteger() - MDN
• Browser support - Can I Use

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Since

2.0.0

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Example

// ❌ Deprecated approach
isInteger(3);        // => true
isInteger(3.14);     // => false
isInteger(Infinity); // => false

// ✅ Recommended approach
Number.isInteger(3);        // => true
Number.isInteger(3.14);     // => false
Number.isInteger(Infinity); // => false

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How it works?

Checks if value is an integer. Deprecated: Use Number.isInteger() directly (ES2015).

Native Equivalent

// ❌ isInteger(value)
// ✅ Number.isInteger(value)

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Use Cases

Check integer value 📌

Verify a value is a whole number.

#integer#whole#number#validate

Number.isInteger(42);    // => true
Number.isInteger(42.5);  // => false
Number.isInteger("42");  // => false

Validate array index

Ensure value is valid for array indexing.

#validate#index#array#integer

if (Number.isInteger(index) && index >= 0) {
  return arr[index];
}

Filter integers

Extract only whole numbers.

#filter#integers#whole

const nums = [1, 2.5, 3, 4.1, 5];
nums.filter(Number.isInteger);
// => [1, 3, 5]