从字符串中提取 email 地址

Question

I have a string like this:

Francesco Renga <francesco_renga-001@gmail.com>

I need to extract only the email, ie francesco_renga-001@gmail.com.

How can I do this in nodejs/javascript in "elegant" way?

Answer 1

Using regex, if your string pattern is always Some text<email> or Some text<email>, Some text<email> <email> you can use this simple one <(.*?)>

Demo

Other solution

Use positive lookahead : [^<]+(?=>) , here is a snippet and a demo

 var text = "Francesco Renga <francesco_renga-001@gmail.com>, Marty McFly <mmcfly@gmail.com> Marty McFly <mmcfly@gmail.com> <mmcfly2@gmail.com>"; var re = /[^< ]+(?=>)/g; text.match(re).forEach(function(email) { console.log(email); }); 

Explanation

[^<]+ match anything but a < between one and unlimited times

(?=>) followed by a >

Simple and does not require any group.

Answer 2

Here's a simple example showing how to use regex in JavaScript :

 var string = "Francesco Renga <francesco_renga-001@gmail.com>"; // Your string containing var regex = /<(.*)>/g; // The actual regex var matches = regex.exec(string); console.log(matches[1]); 

Here's the decomposition of the regex /<(.*)>/ :

• / and / are mandatory to define a regex
• < and > simply matches the two < and > in your string
• () parenthesis "capture" what you're looking for. Here, they get the mail address inside.
• .* : . means "any character", and * means "any number of times. Combined, it means "any character any number of times", and that is inside < and > , which correspond to the place where the mail is.

Answer 3

Here's a simple code showing how extract the unique list of emails address using JavaScript:

let emaillst = string .match(/([a-zA-Z0-9._+-]+@[a-zA-Z0-9._-]+\.[a-zA-Z0-9._-]+)/gi);

            if (emaillst === null) {
                // no Email Address Found
            } else {
                const uniqueEmail = Array.from(new Set(emaillst));
                const finaluniqueEmail = [];
                for(let i=0; i<=uniqueEmail.length; i++){
                    let characterIs = String(uniqueEmail[i]).charAt(String(uniqueEmail[i]).length - 1)
                    if(characterIs==='.'){
                        finaluniqueEmail.push(String(uniqueEmail[i].slice(0, -1)))
                    }else{
                         finaluniqueEmail.push(uniqueEmail[i]);
                    }
                }
                emaillst = finaluniqueEmail.join('\n').toLowerCase();
                console.log(matches[1]);

See the Live Demo of email address extractor online

Features

• Get Unique Emails
• Auto remove duplicate emails
• convert upper case email address to lowercase

Answer 4

for(let i=0; i<=uniqueEmail.length; i++){
                    let characterIs = String(uniqueEmail[i]).charAt(String(uniqueEmail[i]).length - 1)
                    if(characterIs==='.'){
                        finaluniqueEmail.push(String(uniqueEmail[i].slice(0, -1)))

I don't understand why you need this block of code.