Matching a regex in javascript

Question

I'm trying to extract the date from the following strings but to no avail.

 const strs = [ `X March 17th 2011 `, `X 2011 `, `X March 2011 `, ]; console.log(strs.map(s => s.match(/X\\s+([a-zA-Z]+?\\s*[a-zA-Z0-9]+)?\\s*(\\d+)/)) );

The problem is with the first match, currently it is

[
    "X\n       March 17",
    "March",
    "17"
]

while it should be

[
    "X\n           March 17th 2011",
    "March",
    "17th",
    "2011"
]

Any help would be appreciated.

Answer 1

You can use

/X(?:\s+([a-zA-Z]+))?(?:\s+([a-zA-Z0-9]+))?\s+(\d+)/g

See the regex demo . Details :

• X - an X char
• (?:\\s+([a-zA-Z]+))? - an optional sequence of one or more whitespaces ( \\s+ ) and one or more ASCII letters (captured into Group 1)
• (?:\\s+([a-zA-Z0-9]+))? - an optional sequence of one or more whitespaces ( \\s+ ) and one or more ASCII letters or digits (captured into Group 2)
• \\s+ - 1+ whitespaces
• (\\d+) - Group 3: one or more digits

See a JavaScript demo below:

 const strs = ["X\\n March 17th 2011\\n", "X\\n 2011\\n", "X\\n March\\n 2011\\n"]; const rx = /X(?:\\s+([a-zA-Z]+))?(?:\\s+([a-zA-Z0-9]+))?\\s+(\\d+)/; strs.forEach(s => console.log( s.match(rx) ) );

Or, getting full values:

 const strs = ["X\\n March 17th 2011\\n", "X\\n 2011\\n", "X\\n March\\n 2011\\n"]; const rx = /X(?:\\s+[a-zA-Z]+)?(?:\\s+[a-zA-Z0-9]+)?\\s+\\d+/g; strs.forEach(s => console.log( s.match(rx).map(x => x.substr(1).trim().replace(/\\s+/g, ' ') )) );