To check if a string is a valid latitude and longitude combination, we can use a regex expression in JavaScript.

TL;DR

// Regular expression to check if string is a latitude and longitude
const regexExp = /^((\-?|\+?)?\d+(\.\d+)?),\s*((\-?|\+?)?\d+(\.\d+)?)$/gi;

// String with latitude and longitude separated by comma
const str = "9.9824245,76.5703886";

regexExp.test(str); // true

This is the regex expression for matching almost all the test cases for a valid latitude and longitude combination in JavaScript.

// Regular expression to check if string is a latitude and longitude
const regexExp = /^((\-?|\+?)?\d+(\.\d+)?),\s*((\-?|\+?)?\d+(\.\d+)?)$/gi;

Now let's write a string with latitude and longitude like this,

// Regular expression to check if string is a latitude and longitude
const regexExp = /^((\-?|\+?)?\d+(\.\d+)?),\s*((\-?|\+?)?\d+(\.\d+)?)$/gi;

// String with latitude and longitude separated by comma
const str = "9.9824245,76.5703886";

Now to test the string, we can use the test() method available in the regular expression we defined. It can be done like this,

// Regular expression to check if string is a latitude and longitude
const regexExp = /^((\-?|\+?)?\d+(\.\d+)?),\s*((\-?|\+?)?\d+(\.\d+)?)$/gi;

// String with latitude and longitude separated by comma
const str = "9.9824245,76.5703886";

regexExp.test(str); // true

• The test() method will accept a string type as an argument to test for a match.
• The method will return boolean true if there is a match using the regular expression and false if not.

See the above example live in JSBin.

If you want this as a utility function which you can reuse, here it is,

/* Check if string is a valid latitude and longitude  */
function checkIfValidlatitudeAndlongitude(str) {
  // Regular expression to check if string is a latitude and longitude
  const regexExp = /^((\-?|\+?)?\d+(\.\d+)?),\s*((\-?|\+?)?\d+(\.\d+)?)$/gi;

  return regexExp.test(str);
}

// Use the function
checkIfValidlatitudeAndlongitude("9.9824245,76.5703886"); // true
checkIfValidlatitudeAndlongitude("9.2323,1212notValid"); // false

That's all! 😃

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