const regex = /(?:^|(?<=\s))(?!1?\d{10}@)(\w[\w\.]*@\w+\.[\w\.]+)\b/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('(?:^|(?<=\\s))(?!1?\\d{10}@)(\\w[\\w\\.]*@\\w+\\.[\\w\\.]+)\\b', 'gm')
const str = `123456789@test.com // allowed (9 digits or less)
01234567890@test.com // allowed (11 digits but not starting with 1)
123456789012@test.com // allowed (12 digits or more)
0123456789@test.com // NOT allowed (10 digits)
11234567890@test.com // NOT allowed (11 digits and starting with 1)`;
// 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