How can i use Regular Expression with a variable in JavaScript?

Question

This code wants to check an array if the name is in it or not, and that the first letter of all the names in the array is uppercase. There are many users who write their name without using an uppercase letter in their first name.

So I want to pass this condition in the code, by Regular Expression ( /i ), I can use this with a string and some other functions, but I can't use it with a variable.

Can anybody help me?

function runTest() {
    "use strict";
    
    var value = document.getElementById("inin").value;
    
    if (names.indexOf(value) > -1) {
        x.innerHTML = "yes " + value + " your name is here, your are fully approved";
    } else {
        x.innerHTML = "Sorry, Your name isn't here";
    }
}

Make sure you list is all lower or upper case and just transform the incoming value to that case. — Mr. Polywhirl
– Mr. Polywhirl, Commented Nov 30, 2016 at 1:21

Mr. Polywhirl · Accepted Answer · 2016-12-10 18:26:58Z

1

You do not need a regular expression in this case. Just make sure that your list is all lower or upper case and just transform the incoming value to that case.

var outputEl = document.getElementById("output");
var names = [ 'mary', 'bob', 'joseph' ];

function runTest() {
  "use strict";

  var value = document.getElementById("inin").value;

  if (names.indexOf(value.toLowerCase()) > -1) {
    outputEl.innerHTML = "Yes " + value + ", your name is here, you're fully approved.";
  } else {
    outputEl.innerHTML = "Sorry, Your name isn't here.";
  }
}

<input type="text" id="inin" value="Bob" />
<input type="button" value="Test" onClick="runTest()" />
<br />
<span id="output"></span>

edited Dec 10, 2016 at 18:26

answered Nov 30, 2016 at 1:26

Mr. Polywhirl

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2 Comments

Mohamed Aladdin Over a year ago

And, if i want to search on Big string that contains upper and lower case ?! I can't use this way, what will i do ??

Mr. Polywhirl Over a year ago

Example: Your list of names should be transformed to lowercase, initially. Then just transform your input name to lowercase. You will only be dealing with lowercase. There should not be a problem.

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