![]() ![]() replace ( / \s / g, '' ), 10 ) ĭon't use new Number() to compare the numbers. To avoid the similar situations, you should remove all spaces before parsing: parseInt (value. ![]() But be aware that you could get different result when passing a value with spaces as following: parseInt ( ' 5 ' ) // 5 Trim the spaces before parsing the number.īoth Number() and parseInt accept the spaces in input. Since the method could be implemented differently in different versions of JavaScript and browsers, it's recommended to pass the radix number. In the older versions of JavaScript, if the string starts with 0 then the radix is set as 8 (octal). In other cases, the radix is 10 (decimal).If the value starts with 0x or 0X, then the radix is 16 (hexadecimal).In the case it's not specified, then it will be set automatically based on the value. ![]() The second parameter specifies the current numeral system. The parseInt method takes two parameters: parseInt (value, radix ) They return different results when we passing special values such as undefined or null: parseInt ( ) // NaN The second parameter is used to indicate the radix number. On the other hand, Number will try to convert the entire string. ParsingĪs you see, parseInt will parse up to the first non-digit character. Number() converts the type whereas parseInt parses the value of input. IMHO duplicate type checks should not be encouraged.Both Number() and parseInt() are often used to convert a string to number. Adding runtime checks creates bigger bundles and slower code (even if only by a tiny margin). ![]() In my opinion, the type system should allow relaying on the behavior: A string in TypeScript can be converted to a number using an operator called unary plus ( ) operator or using the functions called parseInt function or parseFloat function, or Number function where the unary plus operator converts the numbers represented as a string, Boolean values represented by either true or false and null to numbers. Si la cadena comienza con 0x, es un número hexadecimal. Podemos convertir cadenas vacías, nulo, infinito, true, false en NaN. The radix is an integer between 2 and 36 which represents the base of the number. Producción: Como podemos ver, podemos convertir cualquier cadena en un número. It takes two parameters, the string to be parsed and the radix to be used. The spec gives the function the signature parseInt ( string, radix ) but also states that the argument will be converted to string internally ( Let inputString be ? ToString(string).). JavaScript parseInt () Method: The parseInt () method is used to parse a string and convert it to an integer of a specified radix. :/ const asNumber3 = typeof maybeNumber = 'string' ? parseInt ( maybeNumber, 10 ) : maybeNumber // Or simply accept defeat and out out const asNumber4 = parseInt ( maybeNumber as string, 10 ) But we are still duplicating a type check that already exits in the runtime. toString ( ), 10 ) // Or, better do a type check. const asNumber2 = parseInt ( maybeNumber. const asNumber1 = parseInt ( maybeNumber, 10 ) // So the solution would be: // Convert the number toString() and the string toString() so we can be sure that we never // pass numbers into the parseInt function. Const maybeNumber: number | string = 1 // The issue: parseInt only accepts strings so this fails, // even though the runtime happily accepts any value. ![]()
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