SingleOrDefault

Description:

This method similar to single method . However if the sequence or result of predicate function is empty, it returns null instead of throwing exception.

Sample:

let singleList = ['one'];

let items = ['One', 'Two', 'Three', 'Four', 'Five', 'Six', 'Seven', 'Eight', 'Nine', 'Ten'];

let singleOrDefault = singleList.asEnumerable().singleOrDefault();
console.log(singleOrDefault);

try {
  singleOrDefault = items.asEnumerable().singleOrDefault();
}
catch (err) {
  console.error(err.message);
}

singleOrDefault = items.asEnumerable().singleOrDefault(item => item.indexOf('E') === 0);
console.log(singleOrDefault);

singleOrDefault = items.asEnumerable().singleOrDefault(item => item.indexOf('X') === 0);
console.log(singleOrDefault);

try {
  singleOrDefault = items.asEnumerable().singleOrDefault(item => item.indexOf('F') === 0);
}
catch (err) {
  console.error(err.message);
}