Clean up user-entered phone numbers so that they can be sent SMS messages.
The North American Numbering Plan (NANP) is a telephone numbering system used by many countries in North America like the United States, Canada or Bermuda. All NANP-countries share the same international country code: 1
.
NANP numbers are ten-digit numbers consisting of a three-digit Numbering Plan Area code, commonly known as area code, followed by a seven-digit local number. The first three digits of the local number represent the exchange code, followed by the unique four-digit number which is the subscriber number.
The format is usually represented as
(NXX)-NXX-XXXX
where N
is any digit from 2 through 9 and X
is any digit from 0 through 9.
Your task is to clean up differently formatted telephone numbers by removing punctuation and the country code (1) if present.
For example, the inputs
+1 (613)-995-0253
613-995-0253
1 613 995 0253
613.995.0253
should all produce the output
6139950253
Note: As this exercise only deals with telephone numbers used in NANP-countries, only 1 is considered a valid country code.
Go through the setup instructions for Javascript to install the necessary dependencies:
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Install assignment dependencies:
$ npm install
Execute the tests with:
$ npm test
In the test suites all tests but the first have been skipped.
Once you get a test passing, you can enable the next one by changing xtest
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.
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import { PhoneNumber } from './phone-number';
describe('PhoneNumber()', () => {
test('cleans the number', () => {
const phone = new PhoneNumber('(223) 456-7890');
expect(phone.number()).toEqual('2234567890');
});
xtest('cleans numbers with dots', () => {
const phone = new PhoneNumber('223.456.7890');
expect(phone.number()).toEqual('2234567890');
});
xtest('cleans numbers with multiple spaces', () => {
const phone = new PhoneNumber('223 456 7890 ');
expect(phone.number()).toEqual('2234567890');
});
xtest('invalid when 9 digits', () => {
const phone = new PhoneNumber('223456789');
expect(phone.number()).toEqual(null);
});
xtest('invalid when 11 digits does not start with a 1', () => {
const phone = new PhoneNumber('22234567890');
expect(phone.number()).toEqual(null);
});
xtest('valid when 11 digits and starting with 1', () => {
const phone = new PhoneNumber('12234567890');
expect(phone.number()).toEqual('2234567890');
});
xtest('valid when 11 digits and starting with 1 even with punctuation', () => {
const phone = new PhoneNumber('+1 (223) 456-7890');
expect(phone.number()).toEqual('2234567890');
});
xtest('invalid when 12 digits', () => {
const phone = new PhoneNumber('322234567890');
expect(phone.number()).toEqual(null);
});
xtest('invalid with letters', () => {
const phone = new PhoneNumber('223-abc-7890');
expect(phone.number()).toEqual(null);
});
xtest('invalid with punctuations', () => {
const phone = new PhoneNumber('223-@:!-7890');
expect(phone.number()).toEqual(null);
});
xtest('invalid if area code starts with 0 or 1', () => {
const phone1 = new PhoneNumber('(023) 456-7890');
const phone2 = new PhoneNumber('(123) 456-7890');
expect(phone1.number()).toEqual(null);
expect(phone2.number()).toEqual(null);
});
xtest('invalid if exchange code starts with 0 or 1', () => {
const phone1 = new PhoneNumber('(223) 056-7890');
const phone2 = new PhoneNumber('(223) 156-7890');
expect(phone1.number()).toEqual(null);
expect(phone2.number()).toEqual(null);
});
xtest('invalid when 11 digits starting with 1, '
+ 'but invalid area/exchange code first digits', () => {
const phone1 = new PhoneNumber('1 (023) 456-7890');
const phone2 = new PhoneNumber('1 (123) 456-7890');
const phone3 = new PhoneNumber('1 (223) 056-7890');
const phone4 = new PhoneNumber('1 (223) 156-7890');
expect(phone1.number()).toEqual(null);
expect(phone2.number()).toEqual(null);
expect(phone3.number()).toEqual(null);
expect(phone4.number()).toEqual(null);
});
});
export class PhoneNumber {
constructor(input) {
input = input.replace(/\D/g, "");
if(input[0] === "1"){
input = input.slice(1);
}
this.phoneNumber = input;
}
number() {
if(this.isValid()){
return this.phoneNumber;
}else{
return null;
}
}
isValid() {
return this.validLength() && this.validFirstNumber();
}
validLength() {
return this.phoneNumber.length === 10;
}
validFirstNumber() {
return parseInt(this.phoneNumber[0]) > 1 && parseInt(this.phoneNumber[3]) > 1;
}
}
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