const regex = /^([^a]|a+[^ab]|a+b[ab]*[^abc])*[ab]*$/gim;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('^([^a]|a+[^ab]|a+b[ab]*[^abc])*[ab]*$', 'gim')
const str = `a
ab
abc
abcd
abcab
b
ac
bc
ha
hab
habc
habcd
habcab
haab
haabc
haabcd
haba
habab
hababc
hababcd
ababd
abbd
aabbd`;
// 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