javascript - check if string is in a array without case sensitive [duplicate]

Question

I want to make a filter. Where if you input a word that is in the 'blacklist' it will tell something. I've got all the code but have a problem.

JS:

input = document.getElementById("input").value;
array = ["1","2","3"];
function filter() {
  if (input == array)
  // I will do something.
  } else {
  // Something too
  }
}

I want to make it so that if the input is a item in the array. That the statement is true. But what is the correct way to do this? Because what I'm doing here doesn't work! Also I want to get rid of the case sensitive! So that if the array has hello in it both hello and Hello are detected.

Sorry if this question is asked before. I searched for it but didn't know what keywords to use.

EDIT 1:

I am changing my question a little bit: I want to check what is in my original question but with some other features.

I also want to check if input has a part of an item in array. So that if the input is hello that helloworld is being detected because is has hello in it. As well as hello or Hello.

I think the keyword can be 'javascript array contains some item', 'javascript check item is in array' or 'javascript input is a item in the array(just copy your word)', it should not be hard to think if you know what you want.... — Surely
– Surely, Commented Jun 11, 2015 at 14:14

Mathew Thompson · Accepted Answer · 2015-06-11 14:08:26Z

6

Use indexOf:

if (array.indexOf(input) > -1)

It will be -1 if the element is not contained within the array.

answered Jun 11, 2015 at 14:08

Mathew Thompson

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2 Comments

Roy Berris Over a year ago

Thanks! Is there a way to get rid of the case sensitive, so that if I have hello. In the array both hello and Hello are detected?

Mathew Thompson Over a year ago

@Finiox No probems, you'd have to use map for case insensitivity and map your values into a temporay array containing the uppercase values, then convert your input to uppercase and do the comparison. It's described in detail here: stackoverflow.com/questions/24718349/…

Jan Tchärmän · Accepted Answer · 2015-06-11 14:10:48Z

1

This code should work:

input = document.getElementById("input").value;
array = ["1","2","3"];
function filter() {
   if (array.indexOf(input) >= 0)
      // I will do something.
    } else {
      // Something too
    }
}

The indexOf Method is member of the array type and returns the index (beginning at 0) of the searched element or -1 if the element was not found.

answered Jun 11, 2015 at 14:10

Jan Tchärmän

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1 Comment

Downgoat Over a year ago

The more commonly used is > -1. I would use this to avoid any further confusion for the OP

iurii · Accepted Answer · 2015-06-11 14:08:40Z

0

I think what you are looking for is

input = document.getElementById("input").value;
array = ["1","2","3"];
function filter() {
  if (array.indexOf(input) !== -1 )
  // I will do something.
  } else {
  // Something too
  }
}

answered Jun 11, 2015 at 14:08

iurii

4,2062 gold badges27 silver badges30 bronze badges

2 Comments

Downgoat Over a year ago

If fore some reason indexOf returned undefined, or null, this will return a false positive

iurii Over a year ago

from the doc "This method returns -1 if the value to search for never occurs"

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