Javascript Convert string to number

• You’ve got a string, and it contains a number. Maybe it’s coming from API or some data that you’ve imported.

	const number = '1234';
console.log(number + 1); // 12341
	

			
	
			

		
	

• If you add a number, it just appends items onto the end of the string rather than adding them to the actual Number.

• So, we want to convert this string that contains a number into an actual number.

Using parseInt

Syntax

	parseInt(string, radix);
	

			
	
			

		
	

• string – The value to be parsed. If the parameter is not a string, it is converted to a string.
• radix (optional) From 2 to 36, radix string. For example, specifying 16 means that the parsed value is a hexadecimal number.

	const number = '1234';
console.log(parseInt(number) + 1); // 1235
	

			
	
			

		
	

Using Number Function

Syntax

	Number(object)
	

			
	
			

		
	

• The Number() function converts the object argument to a number that represents the object’s value.

	const number = '1234';
console.log(Number()); // 0
console.log(Number(number)); // 1234
	

			
	
			

		
	

• If you do Not Pass anything, it returns 0.

Using Unary Operator (+)

• Unary operators can be beneficial for converting strings to numbers, and they offer the fastest, most straightforward way to convert.

	const number = '1234';
const un = +number;
console.log(number, typeof number); // 1234 string
console.log(un, typeof un); // 1234 number
	

			
	
			

		
	

Using Multiply with Number

• Multiplying the string with 1 does not change the value and will also be converted to a number.

	const number = '5678';
const mul = number * 1;
console.log(number, typeof number); // 5678 string
console.log(mul, typeof mul); // 5678 number
	

			
	
			

		
	

Using double NOT bitWise operator ( double tilde operator ~~ )

• It is used as a faster substitute for Math.floor() for positive numbers.
• The double tilde operator is not as much an operator as it’s a double NOT bitwise operator / double bitwise negation.

	const number = '1234567';
const negNumber = '-1234567';
const dou = ~~number;
const dou1 = ~~negNumber;
console.log(number, typeof number); // 1234567 string
console.log(dou, typeof dou); // 1234567 number
console.log(dou1, typeof dou1); // -1234567 number
	

			
	
			

		
	

Using Math.floor()

• This method returns the largest integer (floor value) that is less than or equal to the parameter value

	const number = '1234567';
const flo = Math.floor(number);
console.log(flo, typeof flo); // 1234567 number
	

			
	
			

		
	

• It is a Little tricky with decimal numbers since it will return the value of the nearest integer as Number.

	const number = '13.33';
const flo = Math.floor(number);
console.log(flo, typeof flo); // 13 number
	

			
	
			

		
	

	const number = '13.63';
const flo = Math.floor(number);
console.log(flo, typeof flo); //13