如何将字符串与 Javascript 中的模式数组匹配？

Question

I've two variables:

var input = "user1@gmail.com";
var preferredPatterns = ["*@gmail.com", "*@yahoo.com", "*@live.com"];

Want to match the input with preferred pattern array. If any of the patterns matches I've to do certain task (in this example, input is a definite match). How can I match against an array of pattern in javascript?

Answer 1

You can compile your patterns (if they are valid regular expressions) into one for performance:

var masterPattern = new RegExp(patterns.join('|'));

Putting it all together:

var input = 'user1@gmail.com';
var preferredPatterns = [
  ".*@gmail.com$",
  ".*@yahoo.com$",
  ".*@live.com$"
];

var masterPattern = new RegExp(preferredPatterns.join('|'));

console.log(masterPattern.test(input));
// true

Answer 2

You need to use RegExp constructor while passing a variable as regex.

var input = 'user1@gmail.com';
var preferredPatterns = [".*@gmail\\.com$", ".*@yahoo\\.com$", ".*@live\\.com$"];
for (i=0; i < preferredPatterns.length;i++) {
  if(input.match(RegExp(preferredPatterns[i]))) {
     console.log(preferredPatterns[i])
    }
    }

Dot is a special meta-character in regex which matches any character. You need to escape the dot in the regex to match a literal dot.

As @zerkms said, you could use the below list of patterns also.

var preferredPatterns = ["@gmail\\.com$", "@yahoo\\.com$", "@live\\.com$"];

Answer 3

Try this helper function:

/**
 * Returns an integer representing the number of items in the patterns 
 * array that contain the target string text
 */
function check(str, patterns) {
   return patterns.reduce(function (previous, current) {
      return previous + (str.indexOf(current) == -1 ? 0 : 1);
    }, 0);
}

check("user@gmail.com", ["@gmail.com", "@yahoo.com", "@live.com"]; // returns 1
check("user@live.com", ["@gmail.com", "@yahoo.com", "@live.com"]; // returns 0

Answer 4

If you want a general approach to matching against a list of regular expressions then some version of Avinash Raj's answer will work.

Based on the fact that you are specifying certain domains, you might want to match any valid email address using the regex here , and if it matches then check if the domain is a preferred one. There are a number of different ways you could do that of course. Here's just a simple example, splitting on the @ and using jQuery.inArray() to check if the domain is preferred.

var preferredDomains = ["gmail.com", "yahoo.com", "live.com"];

function isValid(inputVal) {
    var re = /^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i;

    return re.test(inputVal) && $.inArray(inputVal.split('@')[1], preferredDomains) > -1;
}

The advantage here is that the underlying regex doesn't change, just the much easier to read/maintain list of domains. You could tweak this to capture the domain in a group, instead of using split().

Answer 5

preferredPatterns.forEach(function(element, index){ 
   if(input.match('/'+element) != null){ 
      console.log('matching  ' + element)  
   }
})

you can write your custom logic if a string matches any pattern.

Answer 6

No regexp you may do as follows;

 function matchPattern(xs, [y,...ys]){ function helper([x,...xs]){ return "*" + xs.join('') === y ? true : xs.length ? helper(xs) : false; } return helper(xs) ? y : ys.length ? matchPattern(xs,ys) : "No Match..!"; } var input = "user1@gmail.com", preferredPatterns = ["*@yahoo.com", "*@live.com", "*@gmail.com"]; result = matchPattern(input, preferredPatterns); console.log(result);

Answer 7

您可以遍历数组，然后使用正则表达式与单个项目进行比较。