Javascript - is there a better way to check an string instead of indexOf

Question

I use this code and My question would be if there is a better way to check a string than indexOf:

if(documentFile.ending.indexOf('pdf') > -1 || documentFile.ending.indexOf('PDF') > -1 || documentFile.ending.indexOf('docx') > -1)

Yeah you have it in ES6. Or you can use regex to do this if (/pdf/i.test(documentFile.ending)) — K D
– K D, Commented Jan 12, 2017 at 14:28
I was thinking regex as well: /pdf/.test(documentFile.ending) — Snowmonkey
– Snowmonkey, Commented Jan 12, 2017 at 14:29
Please define "better". Better in what? What is wrong with indexOf ? — Ivan Sivak
– Ivan Sivak, Commented Jan 12, 2017 at 14:33

Kees van Lierop · Accepted Answer · 2017-01-12 14:30:10Z

2

ES6 has boolean function. Use:

if ( documentFile.ending.includes('pdf') ) { }

Or for regex:

if ( documentFile.ending.match(/your-regex/) { }

Example spec: https://developer.mozilla.org/nl/docs/Web/JavaScript/Reference/Global_Objects/String/includes

answered Jan 12, 2017 at 14:30

Kees van Lierop

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The Reason · Accepted Answer · 2017-01-12 14:30:29Z

0

If you are using ES6 then you may want to look at String.prototype.includes

var str = 'To be, or not to be, that is the question.';
console.log(str.includes('To be'));       // true

answered Jan 12, 2017 at 14:30

The Reason

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2 Comments

The Reason Over a year ago

@Orangesandlemons no it doesnt. have you seen the polyfill for String.prototype.includes ?

user5940189 Over a year ago

sorry, got mixed up with string.includes/indexOf and array.includes/indexOf. Removed original comment

K D · Accepted Answer · 2017-01-12 14:32:05Z

0

In ES6 you have better option to use "includes"

otherwise use regex

if(/pdf/i.test(documentFile.ending))

answered Jan 12, 2017 at 14:32

K D

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Anthony Mills · Accepted Answer · 2017-01-12 14:40:16Z

0

Well, indexOf is really fast, a lot faster than using a regular expression. But something like /pdf$/i.test(str) lets you test the end as well as giving you case-insensitivity. But you could be more precise:

function endsWith(str, ending) {
    return str != null
        && ending != null
        && ending.length <= str.length
        && str.lastIndexOf(ending) === str.length - ending.length;
}

Note the ending.length <= str.length which is there so that you don't do something like endsWith("", "a") and get true. :)

answered Jan 12, 2017 at 14:40

Anthony Mills

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