how to crop string using a pattern in nodejs-CodePudding

I would like to capture the set of characters from a string that matches the pattern using nodejs

ex: const inputString = '     abc 1 2 3  white_rabbit_123_456_789.txt pqr ';
    const pattern = 'white_rabbit_*_*_*.txt'
    expected output is white_rabbit_123_456_789.txt

I am okay if the output is a string or an array.

Also, now lets say I have multiple instances of pattern in the inputString

ex: const inputString = '     abc 1 2 3  white_rabbit_123_456_789.txt pqr 
  white_rabbit_312_456_888.txt';
    const pattern = 'white_rabbit_*_*_*.txt'
    expected output is ['white_rabbit_123_456_789.txt','white_rabbit_312_456_888.txt']

Any suggestion would be very helpful. Thanks!

CodePudding user response：

try this

const inputString1 = '     abc 1 2 3  white_rabbit_123_456_789.txt pqr ';
const inputString2 = '     abc 1 2 3  white_rabbit_123_456_789.txt pqr white_rabbit_312_456_888.txt';

const _match = string => string.match(/white_rabbit_\d _\d _\d .txt/g);

console.log(_match(inputString1));
console.log(_match(inputString2));

CodePudding user response：

You could use String.prototype.match() passing a RegExp argument:

const inputString = `     abc 1 2 3  white_rabbit_123_456_789.txt pqr 
  white_rabbit_312_456_888.txt
  white_rabbit_199212223_8888888_13456787.txt
  white_rabbit_1_2_3.txt
  white_rabbit_444_555_666_777.txt
  white_rabbit_888_999.txt`
const matchArray = inputString.match(/white_rabbit(?:_\d ){3}.txt/g)
console.log(matchArray)

I created a literal RegExp object (pattern between two forward slashes, followed by a global flag), in whose pattern I used a non-capturing group for "an underscore and one-or-more digits" repeated exactly 3 times.