I have two dateString formats like :date-f1:+2 and :date-f2:-1, if the incoming string is in date-f1:+2 format, I need to console.log as processedDate.format("YYYY-MM-DD"), but if the incoming string is in :date-f2:-1 format, I need to console.log as processedDate.format("DD/MM/YYYY"). I have tried the below, but getting an exception Cannot read properties of null (reading '1')", could someone please advise;
let dateString = ":date-f1:+2"; // or ":date-f2:-1"
function datesParse(dateString) {
let matchFormat = dateString.match(/^:date-f1:(|):date-f2:(?:([\-\+])([0-9]+)+)?$/);
let processedDate = moment();
if (matchFormat[1] === "-") {
processedDate = processedDate.subtract(matchFormat[2], 'days');
console.log("Date::"+processedDate.format("DD/MM/YYYY"));
} else if (matchFormat[1] === "+") {
processedDate = processedDate.add(matchFormat[2], 'days');
console.log("Date::"+processedDate.format("DD/MM/YYYY"));
} else if (matchFormat[1] === "-") {
processedDate = processedDate.subtract(matchFormat[2], 'days');
console.log("Date::"+processedDate.format("YYYY-MM-DD"));
} else if (matchFormat[1] === "+") {
processedDate = processedDate.add(matchFormat[2], 'days');
console.log("Date::"+processedDate.format("YYYY-MM-DD"));
}
}
datesParse(dateString);
I modified your regex and also added named capture groups, try this: /^:date-(?<word>f[12]):(?:(?<operator>[-+])(?<number>[0-9]+)+)?$/gm
Test here: https://regex101.com/r/cNNHA5/1
With capture groups you can access each of those captured elements easily:
let line = ':date-f1:+2';
let pattern = /^:date-(?<word>f[12]):(?:(?<operator>[-+])(?<number>[0-9]+)+)?$/gm
let match = pattern.exec(line)
console.log('word', match.groups.word)
console.log('operator', match.groups.operator)
console.log('number', match.groups.number)and use them for checking like:
if (dateString.includes(match.groups.word) && dateString.includes(match.groups.operator))
so you dont have to create extra vars word and operator.