Validate ISBN-10 & ISBN-13 Numbers Validate ISBN-10 and ISBN-13 book identification numbers with check digit verification.

The tool works by first cleaning the input string using JavaScript's replace method with a regular expression to remove any whitespace or hyphens, and then converting it to uppercase using the toUpperCase method. It then checks the length of the cleaned string to determine whether it's an ISBN-10 or ISBN-13 number. For ISBN-10 validation, it uses a weighted sum modulo 11 algorithm, where each digit is multiplied by a weight from 10 to 1, and the last character can be either a digit or 'X', which is treated as 10. The validateIsbn10 function implements this logic using a for loop to calculate the sum. For ISBN-13 validation, it uses an alternating 1-3 weights modulo 10 algorithm, where each digit is multiplied by either 1 or 3 depending on its position, and the result is checked against the last digit of the input string. The validateIsbn13 function implements this logic using a similar approach.

The tool also uses React's useState and useCallback hooks to manage the input state and handle validation, respectively. When the user clicks the "Validate" button or presses Enter, the handleValidate function is called, which in turn calls the validateIsbn function with the current input value. The validateIsbn function returns an object containing a boolean indicating whether the ISBN number is valid, along with an array of details about the validation process, including any error messages or additional information such as the registration group for ISBN-10 numbers. The tool then updates the UI to display the result, using JSX to render the output.

The isbn10to13 function is used to convert an ISBN-10 number to its equivalent ISBN-13 number, by prefixing the first 9 digits with '978' and calculating the check digit using the same algorithm as validateIsbn13. The tool also uses a Record data structure to map the first digit of an ISBN-10 number to its corresponding registration group, such as '0' for English-speaking or '3' for German-speaking. This information is then included in the details array returned by validateIsbn. Overall, the tool relies on a combination of JavaScript algorithms, React hooks, and data structures to provide accurate and detailed ISBN validation.