Number.isInteger()

Why Number.isInteger ?

The Number.isInteger () method checks whether the value to be checked is an integer. Returns “true” if the assigned value is an integer. Returns false if the number is not an integer.

Syntax:

Number.isInteger(value)

• value (required): value to be checked.

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JavaScript Number.isInteger Examples

Example 1

        let val1 = Number.isInteger(1234);
        let val2 = Number.isInteger(1.55);
        let val3 = Number.isInteger(-8.99);
        let val4 = Number.isInteger(0);
        let val5 = Number.isInteger(null);
        let val6 = Number.isInteger("394");
        let val7 = Number.isInteger("truecodes.org");
        let val8 = Number.isInteger(2000 / 1000);
        let val9 = Number.isInteger(Infinity);
        let val10 = Number.isInteger(-Infinity);
        let val11 = Number.isInteger(0 / 0);
        let val12 = Number.isInteger(function () { });
        let val13 = Number.isInteger(2019 / 02 / 03);

        console.log(val1);
        console.log(val2);
        console.log(val3);
        console.log(val4);
        console.log(val5);
        console.log(val6);
        console.log(val7);
        console.log(val8);
        console.log(val9);
        console.log(val10);
        console.log(val11);
        console.log(val12);
        console.log(val13);

output:

true
false
false
true
false
false
false
true
false
false
false
false
false

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Example 2

Returns a positive integer true. If the value to be checked is a negative integer, it returns true.

        let example1 = Number.isInteger(123);
        console.log(example1);

        let example2 = Number.isInteger(-123);
        console.log(example2);

output:

true
true

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Example 3

Returns false if the value to be checked is not a positive integer. If the value to be checked is a negative integer, it returns false.

        let example1 = Number.isInteger(12.3);
        console.log(example1);

        let example2 = Number.isInteger(-12.3);
        console.log(example2);

output:

false
false

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Polyfill

Number.isInteger = Number.isInteger || function(value) {
  return typeof value === 'number' && 
    isFinite(value) && 
    Math.floor(value) === value;
};

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Source:

• https://developer.mozilla.org

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Browser Support

Chrome	yes
Edge	yes
Firefox	16
Internet Explorer	no
Opera	yes
Safari	yes
Android webview	yes
Chrome for Android	yes
Edge mobile	yes
Firefox for Android	16
Opera Android	yes