Validate Phone Numbers

Write a function that returns true if the phone number is in a valid format. Valid formats are as follows:

Examples

validate("578-332-1114") ➞ true

validate("57-332-1114") ➞ false

validate("577 332  1114") ➞ false
// More than one space in between digits clusters.

validate("57 332 1114") ➞ false
// Unacceptable digit cluster length.

validate("157%332-1114") ➞ false
// Unacceptable delimiter.

Notes

• The country code will always be +1 or 1.
• Each phone number will contain either 10 or 11 digits (depending on whether the country code exists).
• There must either be exactly one space, a delimiter, or no space at all between the digit clusters.
• You do not have to worry about extensions.