unable to find string using indexOf in javascript

Question

I am using the function to set the https to the url passed in input.

setHttps(a) {
    if (a.indexOf('http://') > 0){
            a.replace('http', 'https')
            console.log('priting url if...... ', a);
        } else if(a.indexOf('https://') == -1 && a.indexOf('http://') == -1) {
            a = a.replace (/^/,'https://');
            console.log("printing url else........ ", a);
        } 
    return a;
}

When I pass the following:

www.example.com --> converts to ---> https://www.example.com
http://www.example.com --> doesn't get converted to ---> https://www.example.com

Why? It looks like indexOf('http://') is unable to find http:// in the string.

May restrict the replacement to the start of the url, e. g. google.com/search?q=site:http://test.com+test — Jonas Wilms
– Jonas Wilms, Commented Dec 28, 2016 at 9:33

naresh · Accepted Answer · 2016-12-28 09:19:51Z

4

There are atleast 2 issues in your code:

a.indexOf('http://') > 0    // should be >= 0
a.replace('http', 'https')  // replace returns a String

Try the following:

setHttps(a) {
var a = self.previewUrl.value;
if (a.indexOf('http://') >= 0){
        a = a.replace('http', 'https')
        console.log('priting url if...... ', a);
    } else if(a.indexOf('https://') == -1 && a.indexOf('http://') == -1) {
        a = a.replace (/^/,'https://');
        console.log("printing url else........ ", a);
    } 
return a;

}

edited Dec 28, 2016 at 9:19

answered Dec 28, 2016 at 9:12

naresh

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Comments

Pranav C Balan · Accepted Answer · 2016-12-28 10:03:48Z

3

You need to update the variable with returned value. Although use http:// instead of http to avoid matching http in https and index starts from 0 so update condition based on that.

if (a.indexOf('http://') > -1){
    a = a.replace('http://', 'https://')
}

UPDATE : In the else if condition a.indexOf('http://') == -1 is not necessary since it already checked in first if.

setHttps(a) {
    if (a.indexOf('http://') > -1){
            a= a.replace('http://', 'https://')
            console.log('priting url if...... ', a);
        } else if(a.indexOf('https://') == -1) {
            a = a.replace (/^/,'https://');
            // or simply concat
            // a = 'https://' + a;
            console.log("printing url else........ ", a);
        } 
    return a;
}

edited Dec 28, 2016 at 10:03

answered Dec 28, 2016 at 9:12

Pranav C Balan

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2 Comments

Nagaraju Over a year ago

if the variable contains https in it then wont it become httpss

Nagaraju Over a year ago

@naresh would have been better if it was mentioned in the answer

Rosmarine Popcorn · Accepted Answer · 2016-12-28 09:13:01Z

1

In JavaScript grammar "-1" is usually used as sentinel value, and it comes from C.

String.prototype.indexOf method returns the index within the calling String object of the first occurrence of the specified value, starting the search at fromIndex. Returns -1 if the value is not found.

So you'll probably want to do something like :

setHttps(a) {
    var a = self.previewUrl.value;
    if (a.indexOf('http://') > -1){
            a.replace('http', 'https')
            console.log('priting url if...... ', a);
        } else if(a.indexOf('https://') == -1 && a.indexOf('http://') == -1) {
            a = a.replace (/^/,'https://');
            console.log("printing url else........ ", a);
        } 
    return a;
}

answered Dec 28, 2016 at 9:13

Rosmarine Popcorn

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1 Comment

naresh Over a year ago

a = a.replace('http', 'https')

Flying Gambit · Accepted Answer · 2016-12-28 09:52:13Z

1

Read about indexOf

The indexOf() method returns the first index at which a given element can be found in the array, or -1 if it is not present.

Update:

if(a.indexOf('http://') > -1){
   a = a.replace("http", "https");
}else if(a.indexOf('https') === -1){
   a = "https://" + a;
}

edited Dec 28, 2016 at 9:52

answered Dec 28, 2016 at 9:12

Flying Gambit

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Comments

Dashang G. Makwana · Accepted Answer · 2016-12-28 09:12:46Z

0

Check with this code

setHttps(a) {
    if (a.indexOf('http://') > -1){
            a.replace('http', 'https')
            console.log('priting url if...... ', a);
        } else if(a.indexOf('https://') == -1 && a.indexOf('http://') == -1) {
            a = a.replace (/^/,'https://');
            console.log("printing url else........ ", a);
        } 
    return a;
}

answered Dec 28, 2016 at 9:12

Dashang G. Makwana

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Comments

Aditya Singh · Accepted Answer · 2016-12-28 09:13:50Z

0

Change

if (a.indexOf('http://') > 0)

to

if (a.indexOf('http://') > -1)

"http://www.example.com".indexOf('http://') outputs 0 as 'http://' is at that index in the provided URL.

Also, you need to assign the a.replace's output back to a, so the final code would look like this:

function setHttps(a) {
    if (a.indexOf('http://') > -1){
            a = a.replace('http', 'https');
            console.log('priting url if...... ', a);
        } else if(a.indexOf('https://') == -1 && a.indexOf('http://') == -1) {
            a = a.replace (/^/,'https://');
            console.log("printing url else........ ", a);
        } 
    return a;
}

answered Dec 28, 2016 at 9:13

Aditya Singh

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Comments

Nagaraju · Accepted Answer · 2016-12-28 09:24:28Z

0

You need to replace this

if (a.indexOf('http://') > 0)

to

if (a.indexOf('http://') > -1)

It is because, indexOf() returns the index of the first occurrence of the string. Here in your case, the first occurrence of http:// is 0. But, your condition is true if indexOf() > 0. So you need to change the condition so that it would work for 0 also.

edited Dec 28, 2016 at 9:24

Nagaraju

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answered Dec 28, 2016 at 9:16

amulya349

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