How do I check if a string contains only numeric characters in JavaScript without using regular expressions?
Rashid D

To check if a string contains only numeric characters in JavaScript without using regular expressions, you can use various approaches. Here's a long-form answer with different methods: 1. Using a loop andisNaN() function:

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   function isNumericString(str) {
     for (let i = 0; i < str.length; i++) {
       if (isNaN(parseInt(str[i]))) {
         return false;
       }
     }
     return true;
   }

This approach iterates over each character in the string and uses theparseInt() function to convert the character to a number. If the result isNaN, it means the character is not a numeric digit, and the function returnsfalse. If all characters pass the numeric check, the function returnstrue. 2. Using theNumber() function:

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   function isNumericString(str) {
     return !isNaN(Number(str));
   }

This approach converts the entire string to a number using theNumber() function. If the conversion results inNaN, it means the string contains non-numeric characters, and the function returnsfalse. Otherwise, it returnstrue. 3. Using theparseInt() function and strict equality:

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   function isNumericString(str) {
     return String(parseInt(str)) === str;
   }

This approach converts the string to an integer usingparseInt() and then converts it back to a string usingString(). If the resulting string is strictly equal (===) to the original string, it means the string contains only numeric characters, and the function returnstrue. These methods provide different ways to check if a string contains only numeric characters in JavaScript without using regular expressions. Choose the method that best fits your needs and coding style.