const regex = /(?=
[ ]{0,8}? \d{1,9}
( .* ) $ # (1)
)
[ \d]{9}
(?= \1 $ )
/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('(?=
[ ]{0,8}? \\d{1,9}
( .* ) $ # (1)
)
[ \\d]{9}
(?= \\1 $ )
', 'gm')
const str = `examples of valid strings
123456789
kfasdf 3456789asdf
a 1
and examples of invalid strings
12345 789
1 9
a 678a
`;
// Reset `lastIndex` if this regex is defined globally
// regex.lastIndex = 0;
let m;
while ((m = regex.exec(str)) !== null) {
// This is necessary to avoid infinite loops with zero-width matches
if (m.index === regex.lastIndex) {
regex.lastIndex++;
}
// The result can be accessed through the `m`-variable.
m.forEach((match, groupIndex) => {
console.log(`Found match, group ${groupIndex}: ${match}`);
});
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions