CODEWITHSUNDEEP
javascript
RojaS
RojaS

Reputation: 29

javascript Uncaught TypeError for map

I am getting this error if i use map in my script. How to resolve this error?

I am getting this error: Uncaught TypeError: Cannot read property 'map' of null

Js Script:

 var stringval="global $1200"; 
 var getVal=stringval.match(/\d+/g).map(Number);

Upvotes: 0

Views: 47

Answers (1)

Rajesh
Rajesh

Reputation: 24915

String.match return Array<string> | null.

  • If match is found, an array of matched string will be returned.
  • If no match is found, null will be rendered.

So in you case, if the string does not have any number, it will return null causing the script to break.

Sample:

function getNumber(stringval) {
  return stringval.match(/\d+/g).map(Number);
}

var stringval = "global $1200";
console.log(getNumber(stringval))
console.log(getNumber('Hello World'))

A simple way to solve this is to add a check for existence of match:

function getNumber(stringval) {
  // You can set any value based on your requirement
  var defaultValue = undefined;
  var matches = stringval.match(/\d+/g)
  return matches !== null ? matches.map(Number) : defaultValue;
}

var stringval = "global $1200";
console.log(getNumber(stringval))
console.log(getNumber('Hello World'))

Upvotes: 1

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