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How To Convert String To Number in Javascript ?

Last Updated on Wednesday 5th Oct 2022

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


					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



  • 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