### javascript check number and remove decimal when .00

javascript

Here’s a function that takes a number and removes the decimal part if it’s equal to zero:

``````function removeDecimalIfZero(num) {
if (num % 1 === 0) {
return num;
} else {
return num.toFixed(2);
}
}

console.log(removeDecimalIfZero(5.00)); // Output: 5
console.log(removeDecimalIfZero(5.01)); // Output: 5.01``````

This function uses the modulo operator (%) to check if the number is divisible by 1 (i.e., it has no remainder). If it’s divisible, then it returns the number as-is. Otherwise, it returns the number with two decimal places using the toFixed() method.

Note that the toFixed() method returns a string, so if you need a number, you’ll need to convert it back using parseFloat().

``````console.log(removeDecimalIfZero(5.01)); // Output: "5.01"
console.log(parseFloat(removeDecimalIfZero(5.01))); // Output: 5.01``````

# how to check is number when input removeDecimalIfZero(‘5.01’)

To check if the input to the removeDecimalIfZero() function is a number, you can use the typeof operator or the isNaN() function.

Here’s an example using the typeof operator:

``````function removeDecimalIfZero(num) {
if (typeof num === 'number') {
if (num % 1 === 0) {
return num;
} else {
return num.toFixed(2);
}
} else {
return 'Not a number';
}
}

console.log(removeDecimalIfZero('5.01')); // Output: "Not a number"``````

And here’s an example using the isNaN() function:

``````function removeDecimalIfZero(num) {
if (!isNaN(num)) {
if (num % 1 === 0) {
return num;
} else {
return num.toFixed(2);
}
} else {
return 'Not a number';
}
}

console.log(removeDecimalIfZero('5.01')); // Output: "Not a number"``````

Both of these examples will return “Not a number” if the input is not a number. If the input is a number, it will proceed to check if the decimal part is equal to zero and remove it if necessary.

# how to convert to number

To convert a value to a number in JavaScript, you can use the Number() function. For example:

``````console.log(typeof '42'); // Output: string
console.log(typeof Number('42')); // Output: number``````

You can also use the parseInt() function to convert a string to an integer (a whole number). For example:

``````console.log(typeof '42.5'); // Output: string
console.log(typeof parseInt('42.5')); // Output: number
console.log(parseInt('42.5')); // Output: 42``````

Or you can use the parseFloat() function to convert a string to a floating point number (a number with a decimal point). For example:

``````console.log(typeof '42.5'); // Output: string
console.log(typeof parseFloat('42.5')); // Output: number
console.log(parseFloat('42.5')); // Output: 42.5``````

Note that if the string cannot be converted to a number, Number(), parseInt(), and parseFloat() will return NaN (Not a Number). You can use the isNaN() function to check if a value is NaN.

``````console.log(isNaN(Number('hello'))); // Output: true
console.log(isNaN(parseInt('hello'))); // Output: true
console.log(isNaN(parseFloat('hello'))); // Output: true``````

# javascript check decimal when > 0.50 rounding up when < 0.50 rounding down

To round a number up or down in JavaScript based on whether the decimal part is greater than or less than 0.50, you can use the Math.round() function.

Here’s an example that rounds a number up if the decimal part is greater than or equal to 0.50, and rounds it down if it’s less than 0.50:

``````function roundNumber(num) {
if (num % 1 >= 0.50) {
return Math.ceil(num);
} else {
return Math.floor(num);
}
}

console.log(roundNumber(5.49)); // Output: 5
console.log(roundNumber(5.50)); // Output: 6
console.log(roundNumber(-5.49)); // Output: -5
console.log(roundNumber(-5.50)); // Output: -6``````

This function uses the modulo operator (%) to check the decimal part of the number, and the Math.ceil() and Math.floor() functions to round up or down, respectively.

Note that if you want to round to a specific number of decimal places, you can use the toFixed() method instead. For example:

``````console.log((5.49).toFixed(1)); // Output: 5.5
console.log((5.50).toFixed(1)); // Output: 5.5``````

This will round the number to one decimal place. If you want to round to a different number of decimal places, you can adjust the argument passed to toFixed().